单选题（） can be found on most medium to large merchant vessels even if the main engine is either a steam turbine or 2-stroke crosshead engine.A The medium speed 4-stroke trunk piston engineB The low speed 2-stroke crosshead engineC The medium speed 2-stroke

The SOLAS Convention in its successive forms is generally regarded as the most important of all international treaties concerning the ______of merchant ships.

A.pollution

B.economization

C.safety

D.efficiency

The most common type of davit found on merchant vessels today is the ______．

A.Radial

B.Sheath-screw

C.Gravity

D.Quadrantal

You can assume that if all the females in a large pack had pups, ______.

A. only the father would help feed them

B. lions would find and kill them

C. the mothers would fight each other

D. most of the pups would starve

A large oil fire on the deck of a ship can be fought most effectively with ______.

A.dry chemical

B.foam

C.high-velocity fog

D.water (cartridge-operated)、

25． The passage can most probably be found in a ________ book．

A． science

B． history

C． travel

D． maths

Which statement about tunnel bow thrusters fitted to large vessels is TRUE ________．

A.They are effective on most vessels at speeds up to 10 knots

B.Because of their location，most modern installations have as much power as a tug

C.They are fully effective at all drafts

D.When going astern at slow speed，they provide effective steering control

The medium-sized and smaller cities are not so much suitbale for large conventions as Beijing and Shanghai.()

Most propellers on merchant vessels are constructed of______．

A.manganese bronze

B.cast iron

C.mild steel

D.improved plow steel