When making landfall at night，the light from a powerful lighthouse may sometimes be seen before the lantern breaks the horizon．This light is called the ______．A.diffusionB.backscatterC.loomD.elevation
When making landfall at night，the light from a powerful lighthouse may sometimes be seen before the lantern breaks the horizon．This light is called the ______．
A.diffusion
B.backscatter
C.loom
D.elevation
相关考题：
CIn most situations, light helps us see. But nowadays humans are using too much of it so that it is in fact a kind of pollution.When it comes to looking at the night sky, too much light makes it difficult for us to watch some of life’s most wonderful sights: stars, planets and even galaxies(星系).According to scientific research, about 2, 500 stars can be seen by the human eye without using any special equipment(设备). But because of light pollution, you can only see 200 to 300 stars from today’s countryside, and no more than ten stars from a city. In most big cities, people cannot see the sky filled with stars like they did in their childhood.Light pollution affects more than just our view of sky. Research shows that lots of nighttime light can harm wildlife, too.When birds fly to another place over cities, they sometimes get lost by the brightness and fly in circles(圈) until they drop from tiredness. Sea turtles(海龟) need dark beaches for laying eggs, but they can’t find their ideal places because of those bright lights.Too much light at night may even affect human health, but scientists are not sure of that. They are still learning more.In order to prevent things from going worse, governments and some organizations are working to reduce light pollution. Many cities and towns have taken action to reduce the use of lights at night. Lights are used only when and where they are truly needed. They also shine lights down at the ground instead of up into the sky and use lower brightness levels.Hopefully, in the near future, humans can enjoy the clear and beautiful sky again and all the wildlife will live a peaceful and undisturbed life, too.27. Why does the writer think that too much light is a kind of pollution?A. Because there are fewer and fewer stars.B. Because human health has been affected.C. Because too much light is a waste of energy.D. Because some of the wildlife can be harmed.
In English, woman may _________ “Eeek” when they are frightened by something. A.excelB.astonishC.light upD.exclaim
Navigation lights must be displayed in all weathers from sunset to sunrise. They also _____.A.must be displayed when day signals are being usedB.must be displayed when moored to a pierC.may be extingushed at night on open waters when no other vessels are in the areaD.may be displayed during daylight
BThe word “day” has two meanings. When we talk about the number of days in a year, we are using “day” to mean 24 hours. But when we talk about day and night, we are using “day” to mean the time between sunrise and sunset. Since the earth looks like a ball, the sun can shine on only half of it at a time. Always one half of the earth is having day and the other half night. A place is moved from day into night and from night into day over and over by the spinning(旋转) of the earth. At the equator(赤道) day and night are sometimes the same length. They are each twelve hours long. The sun rises at 6 in the morning and sets at 6 in the evening. For six months the North Pole is tilted(倾斜) toward the sun. In those months the Northern Hemisphere(半球) gets more hours of sunlight than the Southern Hemisphere. Days are longer than nights. South of the equator nights are longer than days. For the other six months the North Pole is tilted away from the sun. Then the Southern Hemisphere gets more sunlight. Days are longer than night. North of the equator nights are longer than days. Winter is the season of long nights. Summer is the season of long days.56. When the Western Hemisphere is having day, the Eastern Hemisphere is having ______.A.both day and night B.day C.neither day nor night D.night
The term of Landfall means ________ ．A.Land first sighted when vessel approaching from seawardB.Land last sighted when vessel leaving from a portC.in sight of one another when vessel underwayD.in sight of an island during a ship on her voyage
A pilot vessel on pilotage duty at night will show sidelights and a sternlight ______.A.when at anchorB.only when making wayC.at any time when underwayD.only when the identifying lights are not being shown
When a buoy is in position only during a certain period of the year，where may the dates when the buoy is in position be found?A.Light ListB.Notice to MarinersC.On the chartD.Coast Pilot
Entrance Light Vessel beamed port，stopped eng．& Tug Ever took pilot off．From this remark，the ship is likely ______．A.making inward operationB.making outward operationC.making cargo operationD.at anchor
The traffic lights were red when the driver reached them．To the surprise of his passenger,the ear did not slow down．Unexpectedly the passenger was thrown forward in the vehicle as the driver put on his brakes at the last moment．The car stopped just in time."Sorry,I didn't notice the light．I thought it was green until I saw that it was the top light which was shining."This strange story is quite true．About ten men in every hundred are color blind in some way;women are luckier--only about one in two hundred suffers from color blindness.In some cases,a man may not be able to see deep red．He may think that red,orange and yellow are all the same as green.People often like one color more than others．Blue is the color of the sky and sea．Green makes us think of fields and trees．Red is the color of blood and makes some people think of danger．Black is the color of night．In the dark we cannot see what is around us so we are sometimes afraid of the unknown and do not like black as a color.Among the traffic lights,red light is placed__.A.at the bottomB.in the middleC.at the topD.below the green light
单选题The lighthouse if（）at night may be in trouble.AinvisibleBit is invisibleCisn't visibleDunvisible
单选题Geographic range is the maximum distance at which a light may be seen under（）.Aexisting visibility conditions，limited only by the curvature of the EarthBperfect visibility conditions，limited only by the curvature of the EarthCexisting visibility conditions，limited only by the intensity of the lightDperfect visibility conditions，limited only by interference from background lighting
单选题The nominal range of a light may be accurately defined as the maximum distance at which a light may be seen（）.Aunder existing visibility conditionsBunder perfect visibilityCwith ten miles visibilityDwith fifteen miles visibility
单选题All of the following information concerning lighted aids to navigation may be read directly from the Light List EXCEPT the（）.AlocationBheight of light above waterCluminous rangeDlight characteristics
单选题Sometimes lights are（）by fog，haze，dust，smoke，or precipitation which may be present at the light，or between the light and the observer，and which is possibly unknown by the observer.AobscuredBdarkenedCgreyedDdelighted
单选题When are you allowed to throw plastic garbage overboard?（）ABeing mroe than 25 miles from shoreBOnly at night when it‟s darkCBeing more than 6 miles from shoreDNever
单选题A pilot vessel on pilotage duty at night will show sidelights and a sternlight （）.Awhen at anchorBonly when making wayCat any time when underwayDonly when the identifying lights are not being shown
单选题You are underway and pass by a lighthouse. Its light，which was white since you first sighted it，changes to red. This means（）.Athe light is characterized as alternately flashingBthe lighthouse has lost power and has switched to emergency lightingCit is the identifying light characteristic of the lighthouseDyou have entered an area of shoal water or other hazard
单选题What material may be substituted for zinc when making a poured metal socket ending to a wire rope（）.ALeadBBabbittCSolderDNothing
单选题Small floes of rough，hummocky sea ice capable of damaging a vessel（）.Acan usually be detected by radar in a smooth sea at a range of 4 to 6 kilometersBare indistinguishable from sea return on the PPICare invisible to radar when covered with a thick layer of snowDare usually seen at night before they are close enough to provide a radar echo
单选题A pilot vessel on pilotage duty at night will show sidelights and a stern light （）.Awhen at anchorBonly when making wayCat any time when underwayDonly when the identifying lights are not being shown
单选题The distance from which a certain light is visible is directly proportional to the wattage of the light bulb. If the light is visible from 16 meters when a 40 watt bulb is used, from what distance is the light visible when a 75 watt bulb is used?A30 metersB35 metersC51 metersD89 metersE91 meters
单选题The term of landfall means（）.Aland first sighted when vessel approaching from seawardBland last sighted when vessel leaving from a portCin sight of one another when vessel underwayDin sight of an island during a ship on her voyage
单选题When making landfall at night，you can determine if a light is a major light or an offshore buoy by（）.Athe intensity of the lightBchecking the period and characteristics against the Light ListCthe color，because the buoy will have only a red or a green lightDAny of the above can be used to identify the light
单选题A vessel shall be deemed to be overtaking when she can see at night（）.Aonly the sternlight of the vesselBa sidelight and one masthead light of a vesselConly a sidelight of the vesselDany light except the masthead lights of the vessel
单选题The maximum distance at which a light may be seen under the existing visibility conditions is called（）.Anominal rangeBluminous rangeCcharted rangeDgeographic range