In our class when the bell rang and the teacher closed his book it was a for everyone to

问题补充：

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

A. signal

B. chance

C. mark

D. measure

答案：

(答案→)A. signal

B. chance

C. mark

D. measure

解析：signal信号；chance机会；mark标志；measure测量。句意是在我们课堂上，当铃声响起，老师合起课本时，这是让每个人都起立的信号。故选A。