I.冠词填空：在下列句中空白处填入适当冠词，不需用冠词处划。
1.There is _______ picture of _______ elephant on _______ wall.
2.This is _______ useful book.Ive read it for _______ hour.
3. _______ elephant is much heavier than _______ horse.
4. _______ doctor told him to take _______ medicine three times _______ day.
5.Lets go out for _______ walk.
6.Its too hot.Open _______ door，please.
7.There is _______ woman over there. _______ woman is Meimeis mother.
8. _______ sun rises in _______ east.
9. _______ Changjiang River is _______ longest river in _______ China.
10.Are you going to do it _______ second time?
11.Washington is _______ capital of _______ USA.