I ______ Mr. Smith since he moved to Shanghai.

The letter _____ I received from him yesterday is very important. [ ]

English has large vocabulary, hasn’t it?–Yes, _____ more words and expressions and you will find it easier to read and communicate.

Claudia, are you going to Jeff’s birthday party on Saturday?-Unless I______ .

I will send you an e-mail as soon as I ______ in Canada. 　　[ ]