小行星撞击地球（）。

小行星的轨道（）和地球轨道交叉。

近地小行星中，穿越地球轨道的称为（）

小行星撞击后，地球呈现出哪些景象（）

研究( )为主要特征的城市生态系统时,需要将自然科学和社会科学相结合。

简述生油层的地质特征及主要地球化学特征。

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.

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。