from the still water plane to the crest
from the still water plane to the trough
from crest to trough
between water levels at one-quarter of the wave's length
第1题：
Clearance gauges at bridges indicate ______.
A.the height of the tide
B.depth of water under the bridge
C.charted vertical clearance at mean low water
D.distance from the water to low steel of the bridge
第2题：
Charted depth is the ______.
A.vertical distance from the tidal datum to the ocean bottom plus the height of the tide
B.vertical distance from the tidal datum to the ocean bottom
C.average height of water over a specified period of time
D.average height of all low waters at a place
第3题：
A.wave to you goodbye
B.wave goodbye to you
C.goodbye
D.wave
第4题：
If the radio signal ground wave extends out for less distance than the minimum skywave distance，there is an area in which no signal is received．This is called the ______．
A.Skip zone
B.Blackout zone
C.Diffraction zone
D.Shadow zone
第5题：
Air gap is the vertical distance between the bottom of the hull and the ______．
A.Still water level
B.Wave crest
C.Wave crest plus the charted water depth and tidal corrections
D.Wave crest plus the charted water depth and tidal correction and storm surge
第6题：
Charted depth is the ______.
A.vertical distance from the chart sounding datum to the ocean bottom，plus the height of tide
B.vertical distance from the chart sounding datum to the ocean bottom
C.average height of water over a specified period of time
D.average height of all low waters at a place
第7题：
What should you expect when you encounter a tsunami in the open ocean ________．
A.Violent seas from mixed directions
B.No noticeable change from the existing sea state
C.Winds increasing to gale force from the northwest in the Northern Hemisphere
D.A major wave of extreme height and length
第8题：
The distance between the surface of the water and the tidal datum is the______．
A.height of tide
B.charted depth
C.actual water depth
D.range of tide
第9题：
Spreading oil on the open sea has the effect of ______．
A.Diminishing the height of the seas
B.Lengthening the distance between successive crests
C.Increasing the height of the seas
D.Preventing the wave crests from breaking
第10题：
______:the vertical distance measured on the vessel’s side amidships from the load water line to the upper side of the freeboard deck or a point corresponding to it.
A.Buoyancy
B.Freeboard
C.Draft
D.Displacement