题目内容：

Lifts are very useful. Why? Think about a _______ building. You work _______ the thirtieth floor. Maybe you can walk up all the stairs _______. But can you climb thirty _______ to your office every day?  Of course not.

In an old lift, a worker is needed. He or she operates it _______. In a modern lift, there is no _______. People can operate it _______.

Do you know _______ to use a lift? OK, let me tell you. _______, you want to go to the twelfth floor from the ground floor. First, you must press the button , then the door opens. After that, you can ________ the lift. Third, you press the button, and the __________ closes. Fourth, you press the number 12, then the lift takes you up to the __________ floor. When the door opens again, you can get out of the lift. If you want to ________ down to the first floor, you must press the button, then do the __________. It will take you down there. It is very easy and ________. Now can you use it?

1.A. small    B. tall    C. long    D. nice

2.A. for    B. to    C. of    D. on

3.A. one time    B. much time    C. all the time    D. on time

4.A. building    B. meters    C. steps    D. floors

5.A. in and out    B. up and down    C. on and off    D. here and there

6.A. worker    B. student    C. teacher    D. farmer

7.A. himself    B. herself    C. themselves    D. ourselves

8.A. how    B. what    C. where    D. when

9.A. In the end    B. By the way    C. For example    D. As usual

10.A. get into    B. get up    C. get out of    D. get off

11.A. window    B. door    C. gate    D. box

12.A. twelve    B. twenty    C. twelfth    D. twentieth

13.A. run    B. take    C. walk    D. go

14.A. first    B. different    C. next    D. same

15.A. slow    B. hard    C. fast    D. free