He insisted that he _______ nothing wrong and that he _______ now.

A．did, be freed

B．had done, would be freed

C．should do, should be freed

D．should do, was

变压器一次侧熔断熔丝是作为变压器的（）

A.过负荷保护

B.主保护和二次侧出线短路后备保护

C.二次短路保护

D.备用保护