TIG焊接铝镁合金时，应采用（）焊丝

立焊有两种焊接方向，一种是由（）向（）施焊，叫（）焊；另一种是由（）向（）施焊，叫（）焊。

手工电弧焊有哪些优点？

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。

以下哪些情况会造成提示“Incorrect number or IP address”？（）

逻辑运算符（AND、NOT、OR）的运算顺序是AND→OR→NOT。

TIG 焊焊接不锈钢时用方波(矩形波)交流焊最好。