The velocity of the apparent wind can be more than the true wind，and come from the same direction，if certain conditions are present．One condition is that the ______．A.Ship's speed must be less than the true wind velocityB.True wind must be from dead asternC.True wind velocity must be faster than the ship's speedD.True wind must be from dead ahead
The velocity of the apparent wind can be more than the true wind，and come from the same direction，if certain conditions are present．One condition is that the ______．
A.Ship's speed must be less than the true wind velocity
B.True wind must be from dead astern
C.True wind velocity must be faster than the ship's speed
D.True wind must be from dead ahead
相关考题：
You need to replicate a table from a master to a slave. The master and slave copies of the table will have different number of columns.Which two conditions must be true?() A.Each extra column in the copy with more columns must not have a default valueB.Columns that are common to both versions of the table must be defined in the same order on the master and the slaveC.The slave database cannot have more columns than the master. Only the master database can have more columnsD.Columns that are common to both versions of the table must come first in the table definition, before any additional columns are additional columns are defined on either serverE.The master database cannot have more columns than the slave. Only the slave deatbase can have more columns
If the current and wind are in the same direction，the sea surface represents a wind speed ______.A.lower than actually existsB.higher than actually existsC.that actually existsD.that has no proportional relationship
If the current and wind are in opposite directions，the sea surface represents ______.A.a greatly reduced wind speedB.a higher wind speed than what really existsC.a lower wind speed than what really existsD.more turbulent winds
A weather forecast states that the wind will commence backing. In the Northern Hemisphere this would indicate that it will ______.A.shift in a clockwise mannerB.shift in a counterclockwise mannerC.continue blowing from the same directionD.decrease in velocity
A wind vane on a moving vessel shows ______.A.dead reckoning wind directionB.true wind directionC.apparent wind directionD.estimated wind direction
An anemometer on a moving vessel measures ______.A.apparent wind speed onlyB.true wind speed and true wind directionC.true wind speed onlyD.apparent wind speed and true wind direction
Apparent wind speed blowing across a vessel under tow can be measured by a(n)______．A.barometerB.wind vaneC.anemometerD.Thermometer
共用题干第一篇Renewable Energy SourcesToday petroleum（石油）provides around 40% of the world's energy needs, mostly fuelling automobiles.Coal is still used,mostly in power stations,to cover one-quarter of our energy needs,but it is the least efficient,unhealthiest and most environmentally damaging fossil fuel（矿物燃料）.Natural gas reserves could fill some of the gap from oil,but reserves of that will not last into the 22nd century either. Most experts predict we will exhaust easily accessible reserves within 50 years.Less-polluting renewable energy sources offer a more practical long-term energy solution."Renewable"refers to the fact that these resources are not used faster than they can be replaced.Hydroelectric（水力发电的）power is now the most common form of renewable energy,suDDIvina around 20%of world electricity.China's Three Gorges Dam is the largest ever. At five times the size of the US's Hoover Dam, its 26 turbines（涡轮机）will generate the equivalent energy of 18 coal-fired power stations.It will satisfy 3% of China's entireelectricity demand.In 2003. the first commercial power station to use tidal（潮汐的）currents in the open sea opened in Norway. It is designed like windmill（风车）,but others take the torm ofturbines.As prices fall,wind power has become the fastest growing type of electricity generation一quadrupling（翻两番）worldwide between 1999 and 2005. Modern wind farms consist of turbines that generate electricity.Though it will be more expensive,there is more than enoucih wind to provide the world's entire energy needs.Wind farms come in onshore and offshore forms.They can often end up at spots of natural beauty,and are often unpopular with residents.And turbines are not totally harmless一they can interfere with radar, alter climate and kill sea birds.Scotland is building Europe's largest wind tarm,wnicn will power 200.000 homes.The UK's goal is to generate one-fifth of power from renewable sources,mainly wind,by 2020.But this may cause problems,because wind is unreiiable.According to the passage,resources like wind areA:renewable. B:recyclable.C:damaging. D:scarce.
共用题干第一篇Renewable Energy SourcesToday petroleum（石油）provides around 40% of the world's energy needs, mostly fuelling automobiles.Coal is still used,mostly in power stations,to cover one-quarter of our energy needs,but it is the least efficient,unhealthiest and most environmentally damaging fossil fuel（矿物燃料）.Natural gas reserves could fill some of the gap from oil,but reserves of that will not last into the 22nd century either. Most experts predict we will exhaust easily accessible reserves within 50 years.Less-polluting renewable energy sources offer a more practical long-term energy solution."Renewable"refers to the fact that these resources are not used faster than they can be replaced.Hydroelectric（水力发电的）power is now the most common form of renewable energy,suDDIvina around 20%of world electricity.China's Three Gorges Dam is the largest ever. At five times the size of the US's Hoover Dam, its 26 turbines（涡轮机）will generate the equivalent energy of 18 coal-fired power stations.It will satisfy 3% of China's entireelectricity demand.In 2003. the first commercial power station to use tidal（潮汐的）currents in the open sea opened in Norway. It is designed like windmill（风车）,but others take the torm ofturbines.As prices fall,wind power has become the fastest growing type of electricity generation一quadrupling（翻两番）worldwide between 1999 and 2005. Modern wind farms consist of turbines that generate electricity.Though it will be more expensive,there is more than enoucih wind to provide the world's entire energy needs.Wind farms come in onshore and offshore forms.They can often end up at spots of natural beauty,and are often unpopular with residents.And turbines are not totally harmless一they can interfere with radar, alter climate and kill sea birds.Scotland is building Europe's largest wind tarm,wnicn will power 200.000 homes.The UK's goal is to generate one-fifth of power from renewable sources,mainly wind,by 2020.But this may cause problems,because wind is unreiiable.One of the problems with wind farms is thatA:there is not enough wind.B:wind is not reliable.C:they can only be built on the sea.D:they might influence the world economy.
共用题干Renewable Energy SourcesToday petroleum provides around 40%of the world's energy needs,mostly fuelling automobiles .Coal is still used,mostly in power stations,to cover one-quarter of our energy needs,but it is the least efficient,unhealthiest and most environmentally damaging fossil fuel.Natural gas reserves could plug some of the gap from oil,but reserves of that will not last into the 22nd century either.Most experts predict we will exhaust easily accessible reserves within 50 years.We could fasi reach an energy crisis.We need to rapidly develop sustainable solutions to fuel our future.Lesspolluting renewable energy sources offer a more practical long-term energy solution.They may benefit the world's poor too."Renewable"refers to the fact that these resources are not used faster than they can be replaced.The Chinese and Romans used watermills over 2,000 years ago. But the first hydroelectric dam was built in England in 1870.Hydroelectric power is now the most common form of renewable energy,supplying around 20%of world electricity. China's Three Gorges Dam,which has just been completed,is the largest ever. At five times the size of the US's Hoover Dam,its 26 turbines will generate the equivalent energy of 1 8 coal-fired power stations.It will satisfy 3%of China's entire electricity demand.Surprisingly,some argue that hydroelectric dams significantly contribute green- house gases.In 2003,the first commercial power station to harness tidal currents in the open sea opened in Norway .It is designed like windmill,but others take the form of turbines.As prices fall,wind power has become the fastest growing type of electricity generation-quadrupling worldwide between 1999 and 2005 .Modern wind farms consist of turbines that gener- ate electricity.Though it will be more expensive,there is more than enough wind to provide the world's entire energy needs. Wind farms come in onshore and offshore forms.They can often end up at spots of natural beauty,and are often unpopular with residents.And turbines are not totally benignthey can interfere with radar and leave a significant ecological footprint,altering climate and killing sea birds.Migrating birds may have more luck avoiding them.Scotland is buildingEurope's largest wind farm,which will power 200,000 homes.The UK's goal is to generate one- fifth of power from renewable sources,mainly wind,by 2020 .But this may cause problems,be- cause wind is unreliable. Which of the following statements is true of wind power?A: There is plenty of wind to provide the world's entire energy needs.B: It is the most rapidly growing type of electricity production.C: It may not he reliable.D: All of the above.
共用题干Renewable Energy SourcesToday petroleum（石油）provides around 40% of the world's energy needs, mostly fuelling automobiles .Coal is still used,mostly in power stations,to cover one-quarter of our energy needs, but it is the least efficient, unhealthiest and most environmentally damaging fossil fuel（矿物燃料）.Natural gas reserves could fill some of the gap from oil,but reserves of that will not last into the 22nd century either. Most experts predict we will exhaust easily accessible reserves within 50 years. Less-polluting renewable energy sources offer a more practical long-term energy solution. "Renewable"refers to the fact that these resources are not used faster than they can be replaced.Hydroelectric（水力发电的）power is now the most common form of renewable energy , supplying around 20% of world electricity.China's Three Gorges Dam is the largest ever. At five times the size of the U. S. 's Hoover Dam,its 26 turbines (涡轮机）will generate the equivalent energy of 18 coal-fired power stations. It will satisfy 3%of China's entire electricity demand.In 2003,the first commercial power station to use tidal（潮汐的）currents in the open sea opened in Norway. It is designed like windmill（风车）,but others take the form of turbines.As prices fall,wind power has become the fastest growing type of electricity generation-quadrupling（翻两番）worldwide between 1 999 and 2005 . Modern wind farms consist of turbines that generate electricity. Though it will be more expensive,there is more than enough wind to provide the world's entire energy needs.Wind farms come in onshore and offshore forms. They can often end up at spots of natural beauty,and are often unpopular with residents. And turbines are not totally harmless-they can interfere with radar,alter climate and kill sea birds.Scotland is building Europe's largest wind farm,which will power 200 ,000 homes. The U.K. 's goal is to generate one-fifth of power from renewable sources,mainly wind,by 2020 .But this may cause problems, because wind is unreliable. One of the problems with wind farms is that______.A: there is not enough windB: wind is not reliableC: they can only be built on the seaD: they might influence the world economy
Which three statements about subqueries are true? （）A、A main query can have more than one subquery.B、A subquery can have more than one main query.C、The subquery and main query must retrieve data from the same table.D、The subquery and main query can retrieve data from different tables.E、Only one column or expression can be compared between the subquery and main query.F、Multiple columns or expression can be compared between the subquery and main query.
单选题When evacuating a seaman by helicopter lift，the vessel should be（）.Astopped with the wind dead aheadBstopped with the wind on the beamCunderway with the wind 30°on the bowDunderway on a course to provide no apparent wind
单选题In most cases，the direction of the apparent wind lies between the bow and（）.Athe direction of the true windBtrue northCthe beam on the windward sideDthe beam on the lee side
单选题Which wind results from a land mass cooling more quickly at night than an adjacent water area?（）Acoastal breezeBsea breezeCland breezeDmistral
多选题You need to replicate a table from a master to a slave. The master and slave copies of the table will have different number of columns. Which two conditions must be true?（）AEach extra column in the copy with more columns must not have a default valueBColumns that are common to both versions of the table must be defined in the same order on the master and the slaveCThe slave database cannot have more columns than the master. Only the master database can have more columnsDColumns that are common to both versions of the table must come first in the table definition, before any additional columns are additional columns are defined on either serverEThe master database cannot have more columns than the slave. Only the slave deatbase can have more columns
单选题If the current and wind are in the same direction，the sea surface represents a wind speed （）.Alower than actually existsBhigher than actually existsCthat actually existsDthat has no proportional relationship
单选题The apparent wind can be zero when the true wind is from（）.Aahead and equal to the ship's speedBastern and equal to the ship's speedCahead and equal to twice the ship's speedDastern and equal to twice the ship's speed
单选题The velocity of the wind，its steady direction，and the amount of time it has blown determines a wind driven current’s（）.AtemperatureBdensityCdeflectionDspeed
单选题A weather forecast states that the wind will commence backing. In the Northern Hemisphere，this would indicate that it will（）.Ashift in a clockwise mannerBshift in a counterclockwise mannerCcontinue blowing from the same directionDdecrease in velocity
单选题An anemometer on a moving vessel measures（）.Aapparent wind speed onlyBtrue wind speed and true wind directionCtrue wind speed onlyDapparent wind speed and true wind direction
单选题When evacuating a seaman by helicopter lift，which course should the ship take?（）ADownwind so that the apparent wind is close to nilBA course that will keep a free flow of air，clear of smoke，over the hoist areaCA course that will have the hoist area in the lee of the superstructureDWith the wind dead ahead because the helicopter is more maneuverable when going into the wind
多选题Which three statements about subqueries are true? （）AA main query can have more than one subquery.BA subquery can have more than one main query.CThe subquery and main query must retrieve data from the same table.DThe subquery and main query can retrieve data from different tables.EOnly one column or expression can be compared between the subquery and main query.FMultiple columns or expression can be compared between the subquery and main query.
单选题Apparent wind speed blowing across a vessel under tow can be measured by a(n)（）.AbarometerBwind vaneCanemometerDthermometer
单选题The apparent wind’s speed can be zero only when two conditions are present. One condition is that the true wind（）.Amust be from dead aheadBspeed must be zeroCmust be from dead asternDmust be on the beam
单选题If the current and wind are in opposite directions，the sea surface represents（）.Aa greatly reduced wind speedBa higher wind speed than what really existsCa lower wind speed than what really existsDmore turbulent winds