40．A．be                B．are                 C．were              D．don't

（A）

The students were having their chemistry (化学) class．Miss Li was telling the children what water was like．After that, she asked her students, "What's water?" No one spoke for a few minutes．Miss Li asked again, "Why don't you answer my question? Didn't I tell you what water is like? "

Just then a boy put up his hand and said, "Miss Li, you told us that water has no color and no smell．But where to find such kind of water? The water in the river behind my house is always black and it has a bad smell．" Most of the children agreed with him．

"I'm sorry, children．" said the teacher, "Our water is getting dirtier and dirtier．That's a problem．There is much pollution in our city now．We should do something to protect our environment, right?" the teacher asked．" Yes, we should keep our city clean and keep the water clean．" The students answered together．

39．A．learn               B．have                C．collect             D．find

38．A．for               B．at                  C．into               D．onto

37．A．homework          B．food                C．sleep              D．rest

36．A．healthier            B．stronger              C．better              D．weaker

35．A．sit down           B．get up               C．turn on              D．hurry off

34．A．sleep              B．slept                C．to sleep               D．play

33．A．night              B．noon                C．afternoon           D．morning