---Would you like to go bike riding with us tomorrow?  ---Sure, ____ I am busy.

It’s snowing heavily outside. Put on your coat,_________ ,you’ll catch a cold.

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

Youwillfallbehind others     youwork hard.

We believe _______ we could finally go to a good senior high school.