Question

You were late for class, but you ________ on time．

A. might be
B. should be
C. ought to have been
D. must have been

Answer 1

答案C
ought to have done sth．表示过去应该做而未做某事，相当于should have done sth．;must have done 表示过去肯定做过某事，故选C项。