27. switch on / off the power 开 /关电源

　　28.explain to sb. sth.= explain sth. to sb. 向某人解释某事

　　29. give off 发出（光/热等）

　　30. get / be caught in ... 被困在......中

　　31. require sb. to do sth.

　　　=require that sb. (should ) do sth.要求某人做某事

　　　Sth. require doing / to be done 某物需要被

　　32. be supposed to do 应该

　　33. be equipped with ... 装备有......

　　34. be essential for / to ... 对......是必要的

　　II. Sentences:

　　1. Think about how many changes there have been in the last one thousand years .

　　想想近一千年来有多少变化。

　　2. What problems do you think people in the future will have overcome?

　　你认为，未来的人将已克服了什么问题？

　　3.The air seemed thin as though its combination of gases had little oxygen left.

　　空气似乎很稀薄，好像在混合的气体中剩下的氧气很少。

　　4. Why not sit down and rest? = Why don't you sit down and rest?

　　为什么不坐下休息呢？

　　5. What three visits would you ask to go on if you were Li Qiang ?

　　如果你是李强，你想去哪三个地方看看？

　　6. Neither of these creatures is easy to talk to . 这两种生物都不容易与之交谈。

　　7. The dimpods have so many arms and legs that you can't tell which is which.