If I ____ a candle, I would light the world bright.

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

There are 51 students in Class Three, _____ failed in the test.

The teacher __________ have thought Johnson was worth it or she wouldn’t have wasted time on him, I suppose.

___ with people in the countryside, people in cities can have better education and enjoy various kinds of entertainments[ ]