若某点为二元函数f（x，y）的二阶可微的极大值点，则在这点处（）。

若设定的条件表达式为“＜60 Or＞100”，则表示( )。

下列各点中为二元函数z=x3-y3-3x2+3y-9x的极值点的是（）。

（2010）下列各点中为二元函数z=x3-y3-3x2+3y-9x的极值点的是：（）

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。

下列各点中为二元函数z=x3-y3-3x2+3y-9x的极值点的是（　　）。[2010年真题]

逻辑运算符（AND、NOT、OR）的运算顺序是AND→OR→NOT。