问题

He did well in the examination. He _____ hard at his lessons..

A:must have worked
B:can have worked
C:will have worked
D:has worked

正确答案是：

同类题型

It’s thesort of work that _______a high level of concentration.

The _______ documentary describes _______ in the future.

Lucy is a hardworking and physically active student, ________ has both marks and a fit body.

The new secretary is and therefore the manager is satisfied with her work. [ ]