Where a propeller shaft passes through the hull，water is prevented from entering by means of a（）.

[单选题]“Any leaks in piping, propeller shaft, machinery, tanks, will have to be repaired, or at least patched up temporarily until the next stop” This sentence means that （）.A . Any leaks in piping, propeller shaft, machinery, tanks, will have to be repaire

Rainbows___________when sunlight passes through small drops of water in the sky.

[单选题]（） the cylinder walls, the heat passes through them by conduction.A . When receiving byB . When received byC . In order to receivingD . In order to receive

A dirty stream, for example, often became clear after flowing through plants and

Change the form where necessary.think ... through dedicate ... to strike a balan

[单选题]In the navigation,_______cause the shafting over load most easilyA．stopping the main engine suddenlyB．changing the main engine running direction suddenlyC．the sailing from the shallow water area to the deep water areaD．the ship's trim too much

[主观题]—Where are________ books?—They are on the desk．

[单选题]C．ompared to a constant pitch propeller, a controllable pitch propellerA．more efficiently uses available engine powerB．operates at a lower efficiency at a fixed speedC．produces the same torque at lower engine powerD．develops its rated power at a lowe

[单选题]A． controllable pitch propeller on a diesel driven vessel eliminates the need forA．friction clutchesB．disconnect clutchesC．reversing gearsD．reduction gears

[单选题]A variable pitch propeller is made （） a boss with separate blades mounted into it.A . ofB . up ofC . fromD . out