在下列各句的空白处填入一个最恰当的单词。

1.  The sun _____ in the east and sets in the west.

2.  Please _____ the class into five groups.

3.  The Eiffel Tower in Paris is made of _____ and it is really tall.

4.  It's very cold in the Northeast in winter.  The weather is usually _____ zero.

5.  You should _____ at the door before you enter the teachers' office.

6.  Mickey Mouse is _____ by Walt Disney.

7.  Mike is an _____ boy.  He likes to take part in all kinds of activities.

8.  China has_____ very fast in the past thirty years.

9.  Few people go out to play on such rainy days. They usually stay _____ .

10.  He was walking _____ the school when I said hello to him.