四级练习2011.07.01
[audio]http://sound.yywz123.com/tingbbs/cet4/cet420110701.mp3[/audio]Have you ever wondered how to get out of baby-sitting with your youngest brother or sister? Keep on thinking Maybe you can figure out a machine that will baby-sit for you. That's what a scientism. Dr.B.F.Skinner,has done. He has made a machine to look after babies. He calls this machine a "baby box. The baby box is about as big as a small bed. It is enclosed by glass on the sides and on top. The bottom of the box is like the floor of a small bed. It is always the same temperature in the box.(1)___________________________. Because the baby doesn't have to wear heavy clothes. It can move around freely. In summer the baby never gets too hot. It is also less likely to get sick-- because there are no drafts in the box. In the box,the baby can't hear any outside noise. But you can always hear the baby if it cried. And taking care of the baby box is easy,too. To clean it,you just press a switch.(2)__________________________. To try out the baby box,Dr.Skinner uses it for his baby daughter. He says she likes it very much. She plays in the box and sleeps in it just as other children stay in small beds. She will use the baby box until she is about three years old.(3)_________________________.
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