单斗反铲挖土机、铲运机、推土机、打夯机都属于开挖机械。

履带推土机的传动系，多数采用（）或液力—机械传动形式。

履带式推土机的传动系，多数采用（）或液力机械传动形式。

履带式推土机机械传动方式的主离合器的功用是（）。

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。

TY220推土机的传动系是液力机械式，该推土机的功率是（）马力。

逻辑运算符（AND、NOT、OR）的运算顺序是AND→OR→NOT。