根据句意及首字母提示完成单词

小题1:We went to a summer c______ last year.

小题2:There w______ many trees on the mountains five years ago(以前).

小题3:We are studying hard for e______.

小题4:—He was an English teacher.

—R______?  Did he teach you?

小题5:What an a______ classroom!  It’s too dirty!

为减小设备的震惊，对于用多条传动带传动时，要尽量使传动带长度（）。

A、有伸缩性

B、不等

C、相等

D、有层次