电感L1=10H和L2=20H串联,其等效电感为( )。

电感L1=2H和L2=8H串联,其等效电感为( )。

电感三点式正弦振荡电路的正反馈取自电感，因此，输出波形  （  ）

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.

肋形楼盖中的四边支承板，当l2/l1≥2时，按（）设计；当l2/l1<2时，按（）设计。

逻辑运算符（AND、NOT、OR）的运算顺序是AND→OR→NOT。

电感三点式振荡器的振荡频率比电容三点式振荡器高。（）

三点式振荡器有（）和电感三点式电路。

三点式振荡器电路中振荡回路的三个电抗必须具备什么条件，才能使电路产生自激振荡？为什么？

逻辑运算符（AND、NOT、OR）的运算顺序是AND→OR→NOT。