A lift is very useful.It looks like a small room. It goes up and down all day. Sometimes a worker
stands in the lift. He or she operates (操作) it up and down. In modern lifts there's no worker. People
walk in. They know what floor they want to go. They push a button (按钮) and the lift goes to that floor.
It's very fast and easy.
     Lifts are very important to us. Why? Think about a tall building. Maybe it has twenty floors. Maybe it
has fifty or   (a)   .Who can walk up all the stairs (楼梯)?
     Maybe people can climb them    (b)   .Can someone climb thirty floors to an office every day? Can
small children walk up to their room on the twenty-four floor? Can their mothers or father carry food up
to all those stairs? Of course not. We can have very high buildings because  we have lifts. We could not
have all the beautiful tall buildings without lifts because it is too tired for people to climb the stairs every
day.

根据短文内容，回答问题或完成句子。

1. What is "lift" in Chinese?
                                                                                          
2. What does a worker do when he or she stands in the lift?
                                                                                           
3．根据短文内容，分别写出(a)和(b)处所缺的单词。
   (a)____     ______  (b) ____    ______
4. 将画线句子译成汉语。
                                                                                          
5. Can you give a title for the passage?
                                                                                       __