Genetic engineering began when the DNA molecule(分子), the most basic unit of life, was first described in 1953 by James Watson and Francis Crick. An understanding of DNA led to the altering of normal cell reproduction. Experiments with altering human cells began in 1970. In one of the first experiments, patients were injected with a virus that would produce a life-saving enzyme, but their bodies would not accept it. In 1980 patients with a rare but fatal blood disease were injected with a purified gene that was cloned through DNA technology. Another failure.
Genetic engineering got a legal boost(激励) in 1980. The U.S. Supreme Court said that a patent could be granted on a genetically engineered "oil-eating" bacterium(细菌). This bacterium would help clean up oil spills. The ruling encouraged companies to invent new life forms, and three important medical products were quickly developed.
l Human interferon(干扰素)-- a possible solution to some cancers and viral disease. A newly engineered bacterium produced human interferon as a by-product. This new product reduced the cost of interferon.
l Human growth hormone-- for children whose bodies do not grow to normal height. An expensive growth hormone(荷尔蒙) was previously produced from human cadavers, but by changing the genetic make-up of the single-cell bacterium E. coli, and affordable growth hormone could be produced.
l Human insulin(胰岛素)-- for the treatment of diabetes. People with diabetes used to rely on a beef- or pork-based product until 1982. Now insulin can be manufactured by genetically altered bacteria.
Advances in genetic engineering have continued, though they constantly must be weighted against the safety of procedures. There is clearly much more to discover.
31. This passage is mainly about
A. the effects of altering cells.
B. the human growth hormone.
C. insulin resistance.
D. U.S. Supreme Court rulings.
32. Genetic enginerring may be defined as
A. the altering of normal cell reproduction
B. a branch of applied chemistry.
C. a procedure that holds little promise.
D. a study on life-saving enzymes.
33. According to the passage, human interferon
A. is a hormone that causes disease.
B. could be used to treat cancer.
C. is a viral disease
D. has been cured
34. In this passage, the three genetically engineered medical products are presented
A. as a process.
B. in a simple list.
C. from earliest to latest.
D.as a story.
35. In the last paragraph, the word "weighed" has the cloest meaning with
A. had great influence
B. became a burden.
C. considered carefully.
D. measured accurately.
Puerto Rican Cuisine（菜肴）
Puerto Rico, a Caribbean (加勒比海区) island rich in history and remarkable natural beauty, has a cuisine all its own. Immigration（移民） to the island has helped to shape its cuisine, with people from all over the world making various contributions to it. However, before the arrival of these immigrants, the Taino people lived on the island of Puerto Rico. Taino cuisine included such foods as rodents (啮齿动物), fresh shellfish and fish fried in corn oil.
Many aspects of Taino cuisine continue today in Puerto Rican cooking, but it has been heavily influenced by the Spanish, who invaded Puerto Rico in 1508, and Africans, who were initially brought to Puerto Rico to work as slaves. Taino cooking styles were mixed with ideas brought by the Spanish and Africans to create new dishes. The Spanish extended food choices by bringing cattle, pigs, goats, and sheep to the island. Africans also added to the island's food culture by introducing powerful, contrasting tastes in dishes. In fact, much of the food Puerto Rico is now famous for - coffee, coconuts, and oranges - was actually imported by foreigners to the island.
A common assumption many people make about Puerto Rican food is that it is very spicy(辛辣的). lt's true that chili peppers are popular; aij caballero in particular is a very hot chili pepper that Puerto Ricans enjoy. However, milder(微辣的) tastes are popular too, such as sofrito. As the base of many Puerto Rican dishes, sofrito is a sauce made from chopped onions, green bell peppers, sweet chili peppers, and a handful of other spices. It is fried in oil and then added to other dishes.
36、who lived in Puerto Rico first
D．the Taino people
37、In the first paragraph the word “it” refers to
C．the island’s natural beauty
D．Puerto Rican cuisine
38、what is the main idea of the second paragraph?
A．Taino dishes are important in Puerto Rican cooking
B．Food imported by foreigners isn’t really Puerto Rican
C．Puerto Rican cooking has many outside influences
D．African foods have probably had the most influence
39、How is sofrito used？
A．It is eaten before meals
B．It is added to other dishes
C．It is used where foods are too spicy
D．It is eaten as a main dish
40、 which of the following is NOT true?
A．softito is a type of extremely spicy food
B．Many people think Puerto Rican food is spicy
C．Puerto Rican cuisine uses a lot of chili peppers
D．Aij caballero is a type of chile pepper
"Clean your plate!" and "Be a member of the clean-plate club1!’’ Just about every kid in the US has heard this from a parent or grandparent. Often, it’s accompanied by an appeal： “Just think about those starving orphans in Africa!2" Sure, we should be grateful for every bite of food. Unfortunately, many people in the US take too many bites3. Instead of staying "clean the plate", perhaps we should save some food for tomorrow.
According to news reports, US restaurants are partly to blame for the growing bellies. A waiter puts a plate of food in front of each customer, with two to four times the amount recommended by the government, according to a USA Today story.4 Americans traditionally associate quantity with value and most restaurants try to give them that. They prefer to have customers complain about too much food rather than too little.
Barbara Rolls, a nutrition professor at Pennsylvania State University; told USA Today that restaurant portion sizes began (o grow in the 1970s, the same time that the American waistline began to expand.
Health experts have tried to get many restaurants to serve smaller portions. Now, apparently, some customers are calling for this too. The restaurant industry trade magazine QSR reported last month that 57 percent of more than 4,000 people surveyed believe restaurants serve portions that are too large; 23 percent had no opinion; 20 percent disagreed. But a closer look at the survey indicates that many Americans who can’t afford fine dining still prefer large portions. Seventy percent of those earning at least $150,000 per year prefer smaller portions; but only 45 percent of those earning less than $25,000 want smaller.
It’s not that working class Americans don’t want to eat healthy. It’s just that, "after long hours at low-paying jobs, getting less on their plate hardly seems like a good deal.5 They live frompaycheck to paycheck, happy to save a little money for next year’s Christmas presents.
41、Parents in the United States tend to ask their children
A．not to waste food at meals
B．to save food for tomorrow
C．to wash the dishes clean
D．not to eat too much at meals
42、American restaurants serve large portions because Americans
A．have big bellies
C．want enough nutrition
D．are mostly rich
43、what happened in America in the 1970S?
A．The restaurants began to serve smaller portions
B．Health experts advised people to eat less
C．May American tried to get slim
D．the America waistline started to expand
44、what does the survey indicate?
A．20 percent Americans want smaller portions
B．57 percent Americans earn $150.000 per year
C．Low-income American prefer large portions
D．23 percent Americans earn less than $25.000per year
45、which of the following is NOT true of walking class Americans?
A．they live from paycheck to paycheck
B．they don’t have the habit of saving money
C．they work long hours
D．the want to be healthy eaters