D. the channel of the mussel’s foot

58. To tie itself safely to a new home, a mussel must _____.

A. produce a thread to anchor to the hard surface

B. draw air and water from its pad-like structure

C. hold down a tent as human beings do

D. place many anchor lines strategically
59. Scientists are not thinking of using mussels to produce the super glue mainly because of _____.

A. the possible mass-production of the super glue

B. their concern about the cost of collecting mussels

C. their concern about the extinction of the species
D. the world’s limited demand for the super glue

60. The main idea of this passage is that _____.

A. mussels can be used to produce super glue
B. mussels are much smarter than we think

C. it is important to protect mussels

D. mussels have an amazing power useful to man
56-60 D B D C D

Cloze

In recent years a new farming revolution has begun, one that involves the _61___ of life at a fundamental level – the gene. The study of genetics has_62__ a new industry called biotechnology. As the name suggest, it 63 biology and modem technology through such techniques as genetic engineering. Some of the new biotech companies specialize in agriculture and are working feverishly to 64 seeds that give a high yield, that 65 diseases, drought and frost, and that reduce the need for 66 chemicals. If such goals could be achieved, it would be most 67. But some have raised concerns about genetically engineered crops.

In nature, genetic diversity is created within certain 68 .A rose can be crossed with a different kind of rose, but a rose will never cross with a potato. Genetic engineering, 69 usually involves taking genes from one species and inserting them into another 70 to transfer a desired characteristic. This could mean, for example, selecting a gene which leads to the production of a chemical with anti-freeze 71 from an artic fish, and inserting it into a potato or strawberry to make it frost-resistant. 72, then, biotechnology allows humans to 73 the genetic walls that separate species.

Like the green revolution, 74 some call the gene revolution contributes to the problem of genetic uniformity---some say even more so 75 geneticists can employ techniques such as cloning and 76 culture(培养), processes that produce perfectly 77 copies. Concerns about the erosion of biodiversity, therefore, remain. Genetically altered plants, however, raise new 78, such as the effects that they may have on us and the environment. “We are flying blindly into a new 79 of agricultural biotechnology with high hopes, few constraints, and little idea of the potential 80,” said science writer Jeremy Rifkin.

61. A. manipulation B. management C. manufacture D. maturity

62. A. got along with B. given rise to C. come up with D. lived up to