He is afraid to face the difficulty he thinks he’ll have     the driving test tomorrow; he finds it difficult    rid of the worries．

The cinema was crowded with many people,     many children ______on their parents’ laps.

This is the best way ______ I have thought of ______ the problem.

I still remember __________ chess in class by my teacher about twenty years ago.

—What’s worrying you, dear?—Nothing. I was just thinking about the problem ______ tomorrow.