频率高于20000Hz的声音称为超声；低于20Hz的声音称为（）。

人类听觉所感知声音的频率范围为20Hz~20KHz，其中人耳最敏感的频率范围是300Hz~3000Hz。

人耳能听到的声音频率范围20Hz～20kHz，为保证数字音频还原时不失真，理想的采样频率应为（）。

人耳可感受声音频率的范围为20-20000Hz。声音高于20000Hz为（），低于20Hz为（）。

人耳可听到频率和声压范围是多少，下列组合（）正确 ①声压2HZ×10-5～20N/m2 ②频率20HZ～20KHZ ③声压2HZ×10-5～2N/m2 ④频率2HZ～200KHZ ⑤声压2HZ×10-4～200N/m2 ⑥频率100HZ～200KHZ

Every deliberate act of wrongdoing by the master or any of the crew against the ship or cargo，without the authorization or privity of the Shipowner or his agent，is（）.

（）, or drum is used for hauling in or letting out the wires or ropes which will fasten the ship to the shore.

A salvor may be（）the whole or part of the payment due under Salvage Convention to the extent that the salvage operations have become necessary or more difficult because of fault or neglect on his part or if the salvor has been guilty of fraud or other dishonest conduct.

The （） is used for hauling in or letting out the wires or ropes.

Vessels must be（）valid certificate of nationality or certificated of registry or license.

逻辑运算符（AND、NOT、OR）的运算顺序是AND→OR→NOT。

逻辑运算符（AND、NOT、OR）的运算顺序是AND→OR→NOT。