默认题库 - 海洋学基本知识

单选题

In some parts of the world there is often a slight fall in tide during the middle of the high water period. The effect is to create a longer period of stand at higher water. This special feature is called a(n)（）.

A. apogean tide
B. double high water
C. perigean tide
D. bore

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单选题

In shallow water，waves that are too steep to be stable，causing the crests to move forward faster than the rest of the wave，are called（）.

A. rollers
B. breakers
C. white caps
D. surfer

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单选题

A swift current occurring in a narrow passage connecting two large bodies of water which is produced by the continuously changing difference in height of tide at the two ends of the passage is called a(n)（）.

A. hydraulic current
B. rectilinear current
C. rotary current
D. harmonic current

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单选题

A snag or other underwater obstruction may form a（）.

A. V-shaped ripple with the point of the V pointing upstream
B. V-shaped ripple with the point of the V pointing downstream
C. small patch of smooth water on a windy day
D. smoothing out of the vessel's wake

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单选题

A condition where two currents meet at the downstream end of a middle bar can be determined by a（）.

A. small whirlpool
B. smooth patch of water
C. V-shaped ripple with the point of the V pointing downstream
D. V-shaped ripple with the point of the V pointing upstream

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单选题

The ocean bottom that extends from the shoreline out to an area where there is a marked change in slope to a greater depth is the（）.

A. abyssal plain
B. continental shelf
C. borderland
D. offshore terrace

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单选题

The length of a wave is the length（）.

A. of the wave's crest
B. of the wave's trough
C. measured from crest to trough
D. measured from crest to crest

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单选题

The place where a channel moves from along one bank of the river over to the other bank of the river is called a（）.

A. draft
B. cutoff
C. draw
D. crossing

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单选题

The largest waves (heaviest chop) will usually develop where the wind blows（）.

A. at right angles to the flow of the current
B. against the flow of the current
C. in the same direction as the flow of the current
D. over slack water

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单选题

The drift and set of tidal，river，and ocean currents refer to the（）.

A. position and area of the current
B. speed and direction toward which the current flows
C. type and characteristic of the current's flow
D. None of the above

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