Question

5. In our class, when the bell rang and the taacher closed his book, it was a        or everyone to stand up.

A. signal           B. chance          C. mark          D. measure

Answer 1

 A

解析:

signal 信号； chance 机会； mark 记号； measure  措施。句中的it 代替“铃响时教师合上书”这件事，而“它”正是大家要起立的“信号”。