通过对“声现象”的学习，你认为下列说法中正确的是

A．只要物体振动就一定能听到声音

B．“震耳欲聋”说明声音的音调高

C．在校园内植树可减弱校外传来的噪声

D．超声波的频率很低，所以人听不到

用括号内所给动词的正确形式填空。

1.  — I phoned you yesterday morning, but you were not in. — We ______ (fish) by the river.

2. ______ (make) sure that there are no mistakes, he will check the paper carefully.

3. Is the washing machine I have used for a long time worth ______ (fix)?

4. There ______ (not be) much snow here in the past three years.

5. I don't know if we ______ (show) around the History Museum tomorrow afternoon.