容积效率
参考答案:
液压马达的实际流量与理论流量的比值。
— We need three single rooms for the first week in June.
— ______. The hotel's not busy then. [ ]
A. No problem
B. Don't bother
C. Never mind
D. It doesn't matter
中山纪念堂位于广州市()。
A、越秀区
B、海珠区
C、南沙区
D、黄浦区