我
- A.once a week
- B.once a month
- C.once a year
- D.twice a year
- A.Depth of water at a specific time due to tidal effect
- B.Difference between the depth of the water and the area's tidal datum
- C.Difference between the depth of the water and the high water tidal level
- D.Difference between the depth of the water at high tide and the depth of the water at low tide
- A.yaw
- B.sway
- C.heave
- D.surge
- A.Improperly correcting the other errors in a sextant
- B.The horizon glass not being parallel to the horizon mirror
- C.The horizon glass not being parallel to the index mirror
- D.Human error in taking a celestial observation
- A.Foam should not be used on electrical fires
- B.One kilo of low expansion foam solution produces much more foam
- C.Foam is only efficient when it covers the top of burning combustibles
- D.A stream of foam should be deflected off the deck in order to best agitate the fire
- A.their barometric pressures and temperatures are the same
- B.there are differences in how they track along the jet stream
- C.there are no significant differences between their temperatures and moisture content
- D.there are significant differences between the temperature of each air mass
- A.furnished
- B.painted
- C.prepared
- D.provided
- A.Only on deck
- B.Only in holds
- C.In forecastle，bridge and poop
- D.Both on deck and in holds
- A.decks
- B.bulkheads
- C.joiner work
- D.walls
- A.Sound-powered telephones
- B.Portable radios
- C.Either fixed or portable equipment
- D.All of the above
