水泵的Q~H曲线都是()曲线。离心泵的Q~H曲线()。
参考答案:下降;较缓
--- Shall I phone the hotel for information?
--- There is no need. Sarah said that she would _______ for the weekend.
A.put us through
B.put us up
C.put us out
D.put us down
机场跑道、滑行道标志包括()和等待标志。
A.跑道中线标志
B.精密进近标志
C.滑行道中线标志
D.跑道滑行道交会标志