板块构造学说认为，地壳中比较活跃的地带是（　　）

  注意：1）词数100词左右

        2）可以适当增加细节，使行文连贯

Dear Tom,

Yours,

Li Hua

补全对话

从方框中选择最佳选项完成对话，有两项多余

a. Yes!

b. The keys? They're on the table.

c. No, they aren't.

d. How about my books?

e. It's under the desk.

f. Where are they?

g. Thank you very much.

A: Hi, Susan! My keys（钥匙） are lost（丢失）. ____

B: Are they on the table?

A:____

B: En. . . Are they in your bag?

A: But where is my bag?

B:____

A:____They are here. But there aren't any books in my bag.

B: Ha- ha. Are they lost, too?

A: Oh, no.

B: Look! They are on the shelf (架子).

A:____

B: Not at all.

在图中根据小磁针静止时的指向，标出磁体的N、S极和A点的磁感线方向。