People diet to look more attractive．Fish diet to avoid being beaten up，thrown out of their social group，and getting eaten as a result．That is the fascinating conclusion of the latest research into fish behavior by a team of Australian scientists．

　　The research team have discovered that subordinate(低一等的) fish voluntarily diet to avoid challenging their larger competitors．"In studying gobies we noticed that only the largest two individuals，a male and female，had breeding（繁殖）rights within the group，" explains Marian Wong．"All other group members are nonbreeding females，each being 5-10% smaller than its next largest competitor．We wanted to find out how they maintain this precise size separation．"

　　The reason for the size difference was easy to see．Once a subordinate fish grows to within 5-10% of the size of its larger competitor，it causes a fight which usually ends in the smaller goby being driven away from the group．More often than not，the evicted fish is then eaten up．

　　It appeared that the smaller fish were keeping themselves small in order to avoid challenging the boss fish．Whether they did so voluntarily，by restraining how much they ate，was not clear．The research team decided to do an experiment．They tried to fatten up some of the subordinate gobies to see what happened．To their surprise，the gobies simply refused the extra food they were offered，clearly preferring to remain small and avoid fights，over having a feast．

　　The discovery challenges the traditional scientific view of how boss individuals keep their position in a group．Previously it was thought that large individuals simply used their weight and size to threaten their subordinates and take more of the food for themselves，so keeping their competitors small．

　　While the habits of gobies may seem a little mysterious，Dr．Wong explains that understanding the relationships between boss and subordinate animals is important to understand how hierarchical（等级的）societies remain stable．

　　The research has proved the fact that voluntary dieting is a habit far from exclusive to humans．"As yet，we lack a complete understanding of how widespread the voluntary reduction of food intake is in nature，" the researchers comment．"Data on human dieting suggests that，while humans generally diet to improve health or increase attractiveness，rarely does it improve long-term health and males regularly prefer females that are fatter than the females' own ideal．"

1.When a goby grows to within 5-10% of the size of its larger competitor，it _________．

A．leaves the group itself         B．has breeding rights

C．eats its competitor       D．faces danger

2.The underlined words "the evicted fish" in Paragraph 3 refer to _________．

A．the fish beaten up      B．the fish driven away

C．the fish found out        D．the fish fattened up

3.The experiment showed that the smaller fish _________．

A．fought over a feast     B．preferred some extra food

C．challenged the boss fish      D．went on diet willingly

4.What is the text mainly about?

A．Fish dieting and human dieting．         B．Dieting and health．

C．Human dieting．          D．Fish dieting．

 

How lucky we are today that we can protect ourselves　　56　 many　 57　 that once 　 58　 death to thousands of people. This is because of work of a famous French scientist who suffered a great deal in his own life so that others might　　59　 .

Louis Pasteur was a bright boy,　　60　 his teachers said he was　　61　 . The reason for this was simple. Louis was very　 62　 with everything he did. He wanted to understand all and he asked many questions."Listen," shouted an angry teacher one day. "You are supposed to answer the question　　63　 asking them!"

However, he never stopped asking questions. There was one 　 64　 question he asked:　　65　 what was illness caused? In time he discovered the answers that have helped men　　66　 since ever. He worked very hard to keep　　67　 going on. When the silkworms began　　68　 ,France's silk-makers 　 69　 money. They turned to Pasteur for 　 70　 .

He found out the answer: certain tiny living things called germs attacked the silkworm eggs. Pasteur found a way of 　 71　 these germs, or　　72　 like them. The whole country 　 73　 , but during his years of work three　 74　 died. Even　　75　 he believed that other children's lives could be saved if he could stop germs from spreading.

56. A. against B. through C. without D. away

57. A. enemies B. illnesses C. wars D. dangers

58. A. permitted B. suffered C. meant D. took

59. A. live B. work C. suffer D. die

60. A. even B. though C. and D. so

6１. A. slow B. fool C. foolishly D. clever

62. A. careless B. careful C. satisfied D. unsatisfied

63. A. instead of B. but C. not D. and

64. A. common B. simple C. funny D. special

65. A. from B. by C. since D. though

66. A. to live longer B. to be saved from death C. never to die D. to live

67. A. life B. lives C. persons D. animals

68. A. losing B. dead C. die D. dying

69. A. got B. spent C. made D. lost

70. A. money B. silkworms C. living D. help

71. A. getting rid of B. completing C. separating D. ending

72. A. something B. thing C. creatures D. ones

73. A. were sad B. were silent C. was thankful D. was sorry

74. A. children of the country B. children of his own C. silk-makers D. silkworm eggs

75. A. in the trouble B. in anger C. in his sorrow D. in his joy