Number　 sense is not the ability to count. It is the ability to recognize a 　 1　 in number. Human beings are born with this ability. 2 ，experiments show that many animals are, too. For example, many birds have good number sense. If a nest has four eggs and you remove one, the bird will not　 3 . However, if you remove two, the bird 4 leaves. This means that the bird knows the 　5　 between two and three.

Another interesting experiment showed a bird's 6 number sense. A man was trying to take a photo of a crow(乌鸦)that had a nest in a tower, but the crow always left when she saw him coming. The bird did not 7 until the man left the tower. The man had an 8 .He took another man with him to the tower. One man left and the other stayed, but they did not 9 the bird. The crow stayed away until the second man left, too. The experiment was　 10 with three men and then with four men. But the crow did not return to the nest until all the men were 11 .It was not until five men went into the tower and only four left that they were 12 able to fool the crow.

How good is a human's number sense? It's not very good. For example, babies about fourteen months old almost always notice if something is taken away from a 　13 group. But when the number goes beyond three or four, the children are 14　 fooled.

It seems that number sense is something we have in common with many animals in this world, and that our human 15 is not much better than a crow's.

1. A. rise　　　　　　　 B. pattern　　　　　　　　　　　　　 C. change　　　　　　　　　　 D. trend

2. A. Importantly　 B. Surprisingly　 C. Disappointedly D. Fortunately

3. A. survive　　　　　　　　 B. care　　　　　　　　 C. hatch　　　　 D. notice

4. A. generally 　　　　　　 B. sincerely　　 C. casually　　　　　 D. deliberately

5．A. distance 　　　　　 B. range　　　　 C. different　 　　　 D. interval

6．A. amazing 　　　　　 B. annoying　　　　　 C. satisfying　 D. disturbing

7. A. relax　　　　　　　　　 B. recover　　　　　　 C. react　　　　 D. return

8. A. appointment　　　　 B. excuse　　　　　　 C. idea　　　　　 D. explanation

9. A. fool　　　　　　　　　　 B. hurt　　　　　 C. catch　　　　 D. kill

10.A. repo　　　　　　　　　　　　　 B. repeated　　 C. designed　　 D. approved

11.A. confused　　　　　　 B. gone　　　　 C. tired　　　　　 D. drunk

12.A. gradually　　　　　　 B. luckily　　　 C. strangely　 D. finally

13.　 A. single　　　　　　　 B. small　　　　 C. local　　　　 D. new

14. A. seldom　　　　　　　 B. temporarily C. merely　　　 D. often

15. A. sight　　　　　　　　　 B. nature　　　 C. ability　　　　 D. belief

完形填空

　　DC Hilton was one of the first American to find out that there was money to be made in the middle of the night. 42 years ago be bought a small __1___on US highway 69, in Oklahoma. His___2___customers were truck drivers and___3___salesmen who drank coffee and ate cheese-burgers when they stopped to___4___their journey.

　　It was they who first tried to____5____Hilton to remain open all night. He thought about it for a while, and then suddenly made up his___6____. He took the door key and threw it across the road. He hasn't closed the door____7___.

　　Over the years his simple cafe expanded into a 24-hour roadside ____8___,with a 100-seat restaurant, a petrol station, a mini shopping market, a car ___9___for mobile homes and all-night selfhelp laundry（洗衣店）.

　　Hilton was a ___10__in a 24-hour working trend which has now ___11___ around the world. Today not only restaurants but also hanks, supermarkets, mail-order ___12___and many other businesses are___13___to be open all night. But is this really a good thing?

　　A lot of ____14____has been done in America on the effect of 24-hour working and there is growing ___15____about the long term dangers of society that doesn't sleep.

　　Americans are said to be___16___20％ less than they did 100 years ago, and 55％ claim to __17___at least occasionally from overtiredness. ___18____of the worst man-made accidents happened in the last few hours before ___19___, when even the most experienced night-worker has difficult____20____awake.　　

The number of the patients who recover ________ by 10% every year.

A．rise 　　　　　 B．raises

C．rises 　　　　　 D．lifts