It looked as if they set ________ for home right away.

At that time one knew________ (是怎么回事).

The outside sight looks beautiful________ (一切被雪覆盖着).

________ (有很多活要做) I can't go with you.

The________ (周期) of the seasons makes a year.

Please________(改正) the mistakes in your exercises.

The child used to play________ (恶作剧) on his teachers.

What________ (活动)do you join in after class?

________(决心) is a kind of quality，without which you can't do a thing well.

If you stay in America for a time，you'll learn about a different________(文化).