电路理论中,二孔插座可等效为一个电压源。
A. 对
B. 错
He gave us____ on how to keep fit. A. some advices B. some advice C. an advice D. a advice
A. some advices
B. some advice
C. an advice
D. a advice
Some ___ came to our school for a visit that day.
A. Germans
B. Germen
C. Germany
D. Germanies
Children should make____ for old people in a bus.
A. room
B. a room
C. rooms
D. the room