The signal given to commence lowering the lifeboats is（）.

[单选题]A lifeboat is weight tested by lowering to near the waterand loading to capacity with weight evenly distributed. Itis then lowered into the water and released. This test mustbe done at least once every（）.A . 6 monthsB . 12 monthsC . 18 monthsD . 24 m

[单选题]Prior to lowering the lifeboat，the most important item to check is the（）.A . oarsB . sailC . boat plugD . life preserver

[单选题]英语SIGNAL指（）A .仪表B .开关C .按钮D .信号

[单选题]In the strength of the carrier signal is varied to represent binary 1 or 0.(72) is a system that can map a name to an address and conversely an address to an name.(73) is a three-way handshaking authentication protocol that it's packets are encapsul

[单选题]（）is the most visible signal of distress from a lifeboat at sea in the daytime.A . Smoke signalB . Flash signalC . Fire signalD . Radio emergency transmissio

[单选题]In(66)the strength of the carrier signal is varied to represent binary 1 or 0.(67)is a system that can map a name to an address and conversely an address to al name.(68)is a three-way handshaking authentication protocol that it's packets are encapsu

[名词解释] Signal loss信号损耗

[名词解释] 信号相位（Signal Phase）

[名词解释] 信号斑（signal patch）

[单选题]The alarm signal for engine room catching fire is a blast of random bell followed by____.A．two knocksB．three BlocksC．four knocksD．five knocks