Coral atolls，or a chain of islands at right angles to the radar beam，may show as a long line rather than as individual targets due to ______.A.the effects of beam widthB.limitations on range resolutionC.the pulse length of the radarD.the multiple-target resolution factor
Coral atolls，or a chain of islands at right angles to the radar beam，may show as a long line rather than as individual targets due to ______.
A.the effects of beam width
B.limitations on range resolution
C.the pulse length of the radar
D.the multiple-target resolution factor
相关考题：
The 10-cm radar as compared to a 3-cm radar of similar specifications will ______.A.be more suitable for river and harbor navigationB.provide better range performance on low lying targets during good weather and calm seasC.have a wider horizontal beam widthD.have more sea return during rough sea conditions
The closest point of approach ( CPA ) of a contact on a relative motion radar may be determined ______.A.immediately when the contact is noted on radarB.only if the radar scope is watched constantlyC.after the contact has been marked at least twiceD.by an occasional glance at the radar
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共用题干Caribbean IslandsWhat would you see if you took a cruise to the Caribbean Islands?Palm trees and coconuts（椰子）?White beaches and clear, blue ocean? Colortul corals（珊瑚）and even more colorlu!fishes and birds?You bet.There are thousands of islands in the Caribbean Sea,They are famous for their warm,tropical climate and great natural beauty.The Caribbean Islands form a chain that separates the Caribbean Sea from the rest of the Atlantic Ocean._________(1)Many of the islands were formed by the eruption （爆发）of ancient volcanoes（火山）.Others are low-lying coral islands that gradually rose from the ocean.The Caribbean Islands are known by several names.__________(2)The explorer Christopher Columbus called the islands the Indies in 1492 because he thought he was near the coast of India.Later,Spain and France called the islands the Antilles.There are four large islands in the Caribbean Sea.________(3)These four islands are often called the Greater Antilles.Together,they account for about 90 percent of the land area of the Caribbean Islands.The rest of the Caribbean Islands are much smaller.______(4)You can see why pirates such as the famous Blackbeard sailed these waters.There are countless small islands to bury treasure or hide on.The weather of the Caribbean Sea is almost always warm and sunny.Sandy beaches line the coasts of many islands.__________(5)Many tourists arrive on cruise ships.________（3）A: But life on the Caribbean Islands is not always paradise.B:The earliest name used by Europeans is the Indies,later changed to the West Indies.C: They're like a long necklace that stretches between North and South America.D: They are Cuba,Puerto Rico,Jamaica,and Hispaniola.E: This is why millions of tourists visit the islands each year.F: Some of these islands are no more than tiny slivers（小片）of exposed coral.
共用题干Caribbean IslandsWhat would you see if you took a cruise to the Caribbean Islands?Palm trees and coconuts（椰子）?White beaches and clear, blue ocean? Colorful corals（珊瑚）and even more colorful fishes and birds?You bet.There are thousands of islands in the Caribbean Sea.They are famous for their warm,tropical climate and great natural beauty.The Caribbean Islands form a chain that separates the Caribbean Sea from the rest of the Atlantic Ocean._________(1)Many of the islands were formed by the eruption （爆发）of ancient volcanoes（火山）.Others are low-lying coral islands that gradually rose from the ocean.The Caribbean Islands are known by several names._________(2)The explorer Christopher Columbus called the islands the Indies in 1492 because he thought he was near the coast of India.Later,Spain and France called the islands the Antilles.There are four large islands in the Caribbean Sea._________(3)These four islands are often called the Greater Antilles.Together,they account for about 90 per cent of the land area of the Caribbean lslands.The rest of the Caribbean Islands are much smaller._________(4)You can see why pirates such as the famous Blackbeard sailed these waters.There are countless small islands to bury treasure or hide on.The weather of the Caribbean Sea is almost always warm and sunny.Sandy beaches line the coasts of many islands._________(5)Many tourists arrive on cruise ships._________（3）A:But life on the Caribbean Islands is not always paradise.B:The earliest name used by Europeans is the Indies,later changed to the West Indies.C:They're like a long necklace that stretches between North and South America.D:They are Cuba,Puerto Rico,Jamaica,and Hispaniola.E:This is why millions of tourists visit the islands each year.F:Some of these islands are no more than tiny slivers（小片）of exposed coral.
下列日常生活用语中，表示电话对话的句子是（）AHello, this is Li. May I speak to Chen, please?BHold on, please.CWould you hold the line, please?DWho's calling, please?EI'm sorry. I think you have the wrong number.FI'm sorry, but Chen is not available to come to the phone right now. May I take a message?
The line leading at right angles to the （）(中线) from the forecastle to the shore is called the forward breast line.A、draftB、waterlineC、centerlineD、abeam
单选题A mooring line leading at nearly right angles to the keel is a（）.Abow lineBbreast lineCspring lineDstern line
单选题You are in restricted visibility and hear a fog signal forward of the beam. Nothing appears on your radar screen. You must（）.Astop your enginesBsound two prolonged blasts of the whistleCsound the danger signalDslow to bare steerageway
单选题You hear the fog signal of another vessel forward of your beam.Risk of collision may exist.You MUST（）.AReduce speed to bare steeragewayBStop your enginesCBegin a radar plotDAll of the above
单选题The 10-cm radar as compared to a 3-cm radar of similar specifications will（）.Abe more suitable for river and harbor navigationBprovide better range performance on low lying targets during good weather and calm seasChave a wider horizontal beam widthDhave more sea return during rough sea conditions
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单选题Coral atolls，or a chain of islands at right angles to the radar beam，may show as a long line rather than as individual targets due to （）.Athe effects of beam widthBlimitations on range resolutionCthe pulse length of the radarDthe multiple-target resolution factor
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单选题The closest point of approach (CPA) of a contact on a relative motion radar may be determined（）.Aimmediately when the contact is noted on radarBonly if the radar scope is watched constantlyCafter the contact has been marked at least twiceDby an occasional glance at the radar
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