Tom was a black slave and he at last ______ the cotton farm to join the North Army.

　 A. left 　 B. escaped  C. ran away 　 D. fled

We have done things we ought not to have done and ________ undone things we ought to have done.

　　A. left　　　　　　　　　　　　　B. leave

　　C. will leave　　　　　　　　　　 D. leaving

After the class，the students went out of the classroom one by one, but only Mary______.　　

 A. left B. had left C. was leaving D. was left

It was until last year that he ______.

　 A. left his home town for a new start 　

B. came to realize the importance of leaving English

　 C. worked as an English teacher at a middle school 　

D. set out to build a new house of h his own

These are questions ______ by history.

　 A. left over 　 B. left off  C. leaving out 　 D. leaving behind