It’s five years _____ our teacher came to Jiangyan.

—You look rather tired. _______stop to take a rest？—All right. But I’ll have to work for a few more minutes.

—I’m afraid that I can’t do it.—Oh, you should believe in yourself. You won’t know what you can do______ you try it.

---_______do you send e-mails to your pen friend?  ------Once a month.

Simon improved his way of study. ________, he has made great progress.