Mr White was seen ______ the PalaceMuseum

Isn’t that Ann’s husband over there ?— No, it _______ be him— I’m sure he doesn’t wear glasses.

Many a student____ wearing MP3 players while walking on the streetIt’s quite dangerous

Teachers should _____ their students to practice _____ English as much as possible.

_______ not to miss the early train, we got upahead of time and hurried to the station.