Grown－ups know that people and objects are solid. At the movies, we know that if we reach out to touch Tom Cruise, all we will feel is air. But does a baby have this understanding?

　 To see whether babies know objects are solid, T. Bower designed a method for projecting an optical illusion（视觉影像）of a hanging ball. His plan was to first give babies a real ball, one they could reach out and touch , and then to show them the illusion. If they knew that objects are solid and they reached out for the illusion and found empty air, they could be expected to show surprise in their faces and movements. All the 16-to 24- week -old babies tested were surprised when they reached for the illusion and found that the ball was not there.

　 Grown-ups also have a sense of object permanence. We know that if we put a box in a room and lock the door, the box will still be there when we come back. But does a baby realize that a ball that rolls under a chair does not disappear and go to never-never land?

　 Experiments done by Bower suggest that babies develop a sense of object permanence when they are about 18 weeks old. In his experiments, Bower used a toy train that went behind a screen. When 16－week－old and 22-week-old babies watched the toy train disappear behind the left side of the screen, they looked to the right, expecting it to reappear. If the experimenter took the train off the table and lifted the screen, all the babies seemed surprised not to see the train. This seems to show that all the babies had a sense of object permanence. But the second part of the experiment showed that this was not really the case. The researcher substituted（替换）a ball for the train when it went behind the screen. The 22-week-old babies seemed surprised and looked back to the left side for the train. But the 16-week -old babies did not seem to notice the switch（更换）. Thus, the 16-week-old babies seemed to have a sense of“something permanence, ”while the 22－week－old babies had a sense of object permanence related to a particular object.

1. The passage is mainly about _____.

　 A. babies’ sense of sight　　　　　　 B. effects of experiments on babies

　 C. babies’ understanding of objects　 D. different tests on babies’ feelings

2. In Paragraph 3, “object permanence”means that when out of sight, an object ________.

　 A. still exists　 B. keeps its shape　 C. still stays solid　 D. is beyond reach

3. Which of the following statements is true?

　 A. The babies didn’t have a sense of direction.

　 B. The older babies preferred toy trains to balls.

　 C. The younger babies liked looking for missing objects.

　 D. The babies couldn’t tell a ball from its optical illusion.

　　 sometimes keeps her awake at night 　　　　 Tom is getting more and more quiet at home.

　 A．That; which B．It; that　　 C．Whether; what D．What; that

完形填空

　　Farmer Tom smiles as he looks at his orange trees. The young oranges are growing well in Florida's weather. Warm sunshine and gently rain, along with Tom's 1 , will produce a good crop of oranges this year.

　　But Tom has to 2 Florida's changeable winter weather. In 3 , temperature can destroy Tom's entire orange crop. 4 in Florida for the past 35 years, Tom is prepared for the frosts. When temperature drops below freezing, Tom 5 his crop by watering his orange trees. The water 6 a thin layer of ice around the trees. Strange 7 it may sound, this thin layer of ice actually keeps the 8 . What happens is simple. When the trees 9 , the water loses heat and becomes ice. 10 of the heat it loses is sucked in by the fruit and keeps its temperature 11 . Tom has effectively used this method to save many orange crops.

　　But Tom still faces some difficulties. The trees should be watered 12 the temperature drops to the freezing point. Also, just the right quantity of water must be used. Too much water can form 13 of ice that will break the trees'branches. 14 difficulty is that wind blows away the heat. So Tom has to worry about not only when but also 15 his trees should be watered, and how much water should be used.

　　Computer technology may help Tom 16 . With equipment, air and soil temperatures and wind speed 17 . The information is fed into a computer which can tell when temperature 18 . The computer can correctly decide the quantity of water 19 and how frequently the trees should be watered. Tom will find 20 his orange trees a lot easier with the help of a computer, and will all have the benefits (or advantages) of computer-age oranges.

1．

[　　]

2．

[　　]

3．

[　　]

A．February and March

B．August and September

C．January and February

D．October and November

4．

[　　]

5．

[　　]

6．

[　　]

7．

[　　]

8．

[　　]

9．

[　　]

10．

[　　]

11．

[　　]

12．

[　　]

13．

[　　]

14．

[　　]

15．

[　　]

16．

[　　]

A．with some of these worries

B．to think about these worries

C．to explain reasons

D．to make a plan

17．

[　　]

18．

[　　]

19．

[　　]

20．

[　　]