固体受到撞击会产生（）。
A、声音
B、吸收
C、音乐
参考答案：A
热油泵预热时应不超过（）℃/h的速度升温。
A.40
B.100
C.50
D.25
We all knew from the very ______ that the plan would fail. Now you see it becomes true.
A．outbreak B．outcome C．outflow D．outset
