I’m surprised that he _____ in the exam.

A. should fail    B. would have failed   C. may have failed   D. should have failed

After driving for 20 miles，Jackson realized that he ________in the wrong direction．

  A．was driving       B．drove             C．had been driving    D．had driven

--- Does Li Hua serve in the army?
---No, but he________ in the army for three years.

The novels written by the author sell best, but five years ago no one could have imagined how great a role he _____in the literary world.

 A. was playing            B. was to play          C. had played       D. played

. —Does Li Ping serve in the army?

—No, but he ________ in the army for five years.

A. served B. has served

C. is serving   D. would serve