一次强制循环的循环动力是（）。
A、给水泵；
B、强制循环泵；
C、凝结水泵。
参考答案：A
The pair of socks _ _ very nice. [ ]
A. look
B. looks
C. is looking
D. are looking
— Where is the School English Speech Contest going to be held tonight?
— I’m not sure. Is it in the hall _____ can hold 300 people?
A．where
B．what
C．that
D．when
