用词的适当形式填空
1.he saw UFO while he[ ](walk) down the street.
2.while we[ ](have)dinner,the telephone rang.
3.what[ ]you[ ](do)when your mother came back?
4.he[ ](draw)at eight yesterday evening.
5.i'm[ ](go)to the doctor soon.
6.we[ ](visit)your school next week.
7.it's[ ](sun)today,isn't it?
8.let's[ ](have)a piano lesson.
9.sunday is the[ ](one)day of the week.
10.i have to[ ](study)for a math test.