He did not regret saying what he did but felt that he _________ it differently.

The boy         the first prize, but he was so careless as to make a foolish mistake.

———It was a green dinner. _______ 
———Thanks. But it really only took an hour.

It is often recommended that children ________chances to get close to nature.

I really don’t know how to express my thanks to Mr. Li, my high school English teacher, without whose help I__________ to college that year.

If you were to do it,the result______different.

It was playing computer games that cost the boy plenty of time that he ______ spent doing his lessons.

"They didn’t take measures in time, otherwise the explosions ____．"some experts said．

—You ought to have made an apology to Tom yesterday evening．
—Yes, I know I __       __．

Why is so silent in the room? He _________asleep in the room.