变压器的分接开关作用是( )。

A．改变副绕组匝数，调节副绕组的输出电压

B．改变变压器的运行方式

C．改变原绕组的匝数，调节副绕组的输出电压

D．对电路进行分断和关合

.

Not only ________ many people's lives by reducing fever, but _______ other things that aspirin can help with.

A aspirin has saved, there also are      B has aspirin saved, there are also

C aspirin has saved, are there also       D has aspirin saved, are there also