Teenagerstheir health because they play computer games too much.

The teacher told me _________when I left the classroom.

Listen! Is Mary singing in the next room—No. It _______ be Mary．She has gone to Shanghai for an important meeting.

I got close enough to hear them speaking Chinese, and I said “Ni Hao ” just as I ____ do in China. [ ]

His father _____ to Nanjing. He _____ back next week.