—Does he know how to work out the problem?---Yes, he has ___ a good idea to solve it.     ----Yes, he has ___ a good idea to solve it.

We had waited for a long time before the famous singer     .

After all，he is only a child.______ him ______ what he has done and give him a chance to correct his mistake.

Air and the sun's rays create much distortion, and whatever tends to _____ their influence is useful to the astronomer.

You'll have to be patient ______ my mother ----she's going rather deaf, which ,after all，also makes her badly cut ______.