首次启动的3G型三螺杆泵,要将泵内充满()后再启动。
A、空气
B、蒸汽
C、油
D、热水
参考答案:C
成()时,单数士兵在左,双数士兵在右。
A、班二路纵队
B、班二列横队
C、班横队
D、班纵队
That art centre is______used to be a factory,________millions of cars were made in.
A. what; which
B. where;where
C. what; where
D.where; which