Question

—Susan stays alone in the classroom and looks sad.
—_____________to her?
A What happens           B What has happened
C What is happening       D What was happening

Answer 1

B

B “某人发生了某事”即sth. happen to sb.，happen一般不用于进行时；Susan不高兴，说明是（已经）发生了某事，故用完成时，且完成时表示不高兴的原因。