Humans have altered the world’s climate by (1) heat-trapping gases since almost the beginning of civilization and even prevented the start of an ice age several thousand years ago, a scientist said.
Most scientists (2) a rise (3) global temperatures over the past century (4) to emissions of carbon dioxide (5) human activities like driving cars and operating factories.
Dr. William Ruddiman, a professor at the University of Virginia, said at a meeting of the American Geophysical Union (6) humans’ effect (7) climate went back nearly 10, 000 years (8) people gave up hunting and gathering and began farming.
In a commentary accompanying the article, Dr. Thomas J. Crowley of Duke University, said he (9) Dr. Ruddiman’s premise at first. "But when I started reading, Dr. Crowley wrote, "I could not help but (10) whether he just might be (11) something."
The climate of the last 10,000 years has been unusually stable, (12) civilization to flourish. But that is only because people chopped down swaths of forest in Europe, China and India for croplands and pastures. Carbon dioxide (13) by the destruction of the forests, plus methane, another heat-trapping gas, (14) by irrigated rice fields in Southeast Asia, trapped enough heat to (15) an expected natural cooling.
Levels of carbon dioxide and methane rise and fall in natural cycles (16) thousands of years, and both reached a peak at the end of the last ice age 11 ;000 years ago. Both then declined (17) expected.
Both (18) declining through the present day, leading to lower temperatures, and a new ice age should have begun 4,000 to 5,000 years ago, Dr. Ruddiman said. Instead, levels of carbon dioxide reversed 8,000 wears ago. The decline (19) methane levels reversed 5,000 years ago, (20) with the advent of irrigation rice farming.

A:to B:for C:as D:since

Some of the concerns surrounding Turkey’s application to join the European Union, to be (1) on by the EU’s Council of Ministers on December 17th, are economic--in particular, the country’s relative poverty. Its GDP per head is less than a third of the average for the 15 pre-2004 members of the EU. (2) it is not far off that of Latvia--one of the ten new members which (3) on May 1st 2004, and it is much the same as (4) of two countries, Bulgaria and Romania, which this week concluded (5) talks with the EU that could make them full members on January 1st 2007.
(6) , the country’s recent economic progress has been, according to Donald Johnston, the secretary-general of the OECD, stunning. GDP in the second quarter of the year was 13.4% higher than a year earlier, a (7) of growth that no EU country comes close to (8) . Turkey’s (9) rate has just fallen into single figures for the first time since 1972, and this week the country (10) agreement with the IMF on a new three-year, $10 billion economic program that will help Turkey (11) inflation toward European levels, and enhance the economy’s resilience.
Resilience has not historically been the country’s economic strong point. (12) , throughout the 1990s growth oscillated like an electrocardiogram (13) a violent heart attack. This (14) has been one of the main reasons why the country has failed dismally to attract much-needed foreign direct investment. Its stock of such investment is lower now than it was in the 1980s, and annual (15) have scarcely ever reached $1 billion.
One deterrent to foreign investors is due to (16) on January 1st 2005. On that day, Turkey will take away the right of virtually every one of its citizens to call themselves a millionaire. Six zeros will be removed from the face value of the lira (里拉，土耳其货币单位); one unit of the local (17) will henceforth be worth what 1 million are now--ie, about ￡ 0.53 (0.53 欧元). Goods will have to be (18) in both the new and old lira for the whole of the year, (19) foreign bankers and (20) can begin to look forward to a time in Turkey when they will no longer have to juggle mentally with indeterminate strings of zeros.

A:though B:but C:for D:since

Most worthwhile careers require some kind of specialized training. Ideally, therefore, the choice of an (1) should be made even before choice of a curriculum in high school. Actually, (2) , most people make several job choices during their working lives, (3) because of economic and industrial changes and partly to improve. (4) position. The "one perfect job" does not exist. Young people should (5) enter into a broad flexible training program that will (6) them for a field of work rather than for a single (7) .
Unfortunately many young people have to make career plans (8) benefit of help from a competent vocational counselor or psychologist. Knowing (9) about the occupational world, or themselves for that matter, they choose their lifework on a hit-or-miss (10) . Some drift from job to job. Others (11) to work in which they are unhappy and for which they are not fitted.
One common mistake is choosing an occupation for (12) real or imagined prestige. Too many high school students or their parents for them choose the professional field, (13) both the relatively small proportion of workers in the professions and the extremely high educational and personal (14) . The imagined or real prestige of a profession or a "white-collar" job is (15) good reason for choosing it as life’s work. (16) , these occupations are not always well paid. Since a large proportion of jobs are in mechanical and manual work, the (17) of young people should give serious (18) to these fields.
Before making an occupational choice, a person should have a general idea of what he wants (19) life and how hard he is willing to work to get it. Some people desire social prestige, others intellectual satisfaction. Some want security; others are willing to take (20) for financial gain. Each occupational choice has its demands as well as its rewards.

A:since B:therefore C:furthermore D:forever

Generally speaking, a British is widely regarded as a quiet, shy and conservative person who is (1) only among those with whom he is acquainted. When a stranger is at present, he often seems nervous, even (2) . You have to take a commuter train any morning or evening to (3) the truth of this.
Serious-looking businessmen and women sit reading their newspapers or dozing in a corner; hardly anybody talks, since to do so would be considered quite (4) .
(5) , there is an unwritten but clearly understood code of behavior which, once broken, makes the offender immediately the object of (6) .
It has been known as a fact that a British has a (7) for the discussion of their weather and that, if given a chance, he will talk about it (8) .
Some people argue that it is because the British weather seldom (9) forecast and hence becomes a source of interest and (10) to everyone.
This may be so. (11) a British cannot have much (12) in the weathermen, who, after promising fine, sunny weather for the following day, are often proved wrong (13) a cloud over the Atlantic brings rainy weather to all districts! The man in the street seems to be as accurate — or as inaccurate — as the weathermen in his (14) .
Foreigners may be surprised at the number of references (15) weather that the British (16) to each other in the course of a single day. Very often conversational greetings are (17) by comments on the weather. “Nice day, isn’t it” “Beautiful!” may well be heard instead of “Good morning, how are you” Although the foreigner may consider this exaggerated and comic, it is (18) .pointing out that it could be used to his advantage. If he wants to start a conversation with a British but is at a loss to know (19) to begin, he could do well to mention the state of the weather. It is a safe subject which will (20) an answer from even the most reserved of the British.

A:since B:once C:when D:while

Most worthwhile careers require some kind of specialized training. Ideally, therefore, the choice of an (1) should be made even before the choice of a curriculum in high school. Actually, (2) , most people make several job choices during their working lives, (3) because of economic and industrial changes and partly to improve (4) position. The "one perfect job" does not exist. Young people should (5) enter into a broad flexible training program that will (6) them for a field of work rather than for a single (7) .
Unfortunately many young people have to make career plans (8) benefit of help from a competent vocational counselor or psychologist. Knowing (9) about the occupational world, or themselves for that matter, they choose their lifework on a hit-or-miss (10) .Some drift from job to job. Others (11) to work in which they are unhappy and for which they are not fitted.
One common mistake is choosing an occupation for (12) real or imagined prestige. Too many high school students-or their parents for them-choose the professional field, (13) both the relatively small proportion of workers in the professions and the extremely high educational and personal (14) . The imagined or real prestige of a profession or a "white collar" job is (15) good reason for choosing it as life’s work. (16) , these occupations are not always well paid. Since a large proportion of jobs are in mechanical and manual work, the (17) of young people should give serious (18) to these fields.
Before making an occupational choice, a person should have a general idea of what he wants (19) life and how hard he is willing to work to get it. Some people desire social prestige, others intellectual satisfaction. Some want security, others are willing to take (20) for financial gain. Each occupational choice has its demands as well as its rewards.

A:since B:therefore C:furthermore D:forever

Dear Mr. Mills,
In reply to your letter of April 20, I would (21) to inform(通知) you that there are a (22) of beautiful summer cottages(小别墅) for sale here in Ocean City.
For example, we have a modern two-storey house that is (23) up to date. It is two blocks from the sea and you may find this a disadvantage(不利), but, (24) all, the opening of the summer (25) is only a few weeks from now, and finding a house (26) to the ocean than that is (27) out of the question. The house I’m speaking of has two bedrooms and a porch(门廊) that can be (28) for sleeping. For this reason, I consider it as a very good buy. The plumbing(给水管道) is out of order at the (29) , but this will be repaired, of course. The price is reasonable; as a matter of fact, it is less than is being asked for comparable(同等的) houses elsewhere in town.
As a rule, I (30) to deal with people face to face in matters of this kind. (31) , I will be out of town next week, and I don’t think you should delay in (32) your decision about this house, since it is sure to be sold quickly. Under the circumstances (环境), (33) , I suggest that you come to see it as (34) as possible. You can deal with one of my assistants in the office. I am sure you will find the house is (35) what you expect.
Sincerely yours,
Jason Riggs, Manager
Ocean City Real Estate Company

A:so B:therefore C:thus D:since

He (lived) in Beijing (since) 1980 to 1997, but he (is now living) (in) Shanghai.

A:lived B:since C:is now living D:in

(Since the beginning) of this century, more and more scientists (have become) interested (in) (the way how) the human brain works.

A:Since the beginning B:have become C:in D:the way how