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:lasting B:lasted C:last D:have lasted

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:lasting B:lasted C:last D:have lasted

I caught the last bus from town, but Harry came home （　）that night.

A:very late B:even later C:the same late D:the last one

I am an American. Perhaps that (1) me a little biased, but I believe that the American presidency is the most (2) . job in the world. It’s a job that goes up for grabs (3) four years. The candidate who wins in November of 2000 will take office the following January and be the (4) new U.S. president of the twenty-first century.
The election campaign is a (5) one. Some say it begins right after the election and goes on for the next (6) years. That’s probably an exaggeration, but it does last a long time. Those who have their eyes on the job have to start (7) support and building campaign organizations early.
Some believe that the campaign for president should be (8) . I disagree. A long campaign is an endurance contest. It gives the (9) a chance to show their strengths and (10) them to betray their weaknesses. The extended scrutiny makes it much less likely that the (11) will accidentally choose an unqualified candidate to be their leader.
(12) , I enjoy the contest. It’s a marathon that produces a (13) who may have a profound effect (14) all our lives. You can have your playoffs and your championships; the debates, primaries, conventions, and November (15) are the sporting events that really matter!

A:young B:last C:old D:first

I shouldn’t let it bother me. It really doesn’t matter anyway. But it does bother me ! All those people are preparing to (21) a new century, a new millennium (千年) as well. And it just isn’t (22) !
Most of us schedule our lives by the Gregorian (23) . Our years are measured from the (24) of Christ. The first year of the first century is 1, or 1 A.D. The last year of that century is the year 100. Simple Yes! A century is 100 (25) long. A millennium is 1,000 years long, which is (26) ten centuries.
Since the last year of the first century is the year 100, the first year of the (27) century is 101. Follow that pattern, century by century and you’ll get my (28) . The year 2000 is the last year of the twentieth century. After all, (29) thousand means twenty hundreds. Twenty hundred years means twenty centuries. The year 2000 is the (30) , the final, the one that’s still here, year of the twentieth century!!!!
I know, I’m getting too (31) . But it isn’t fair, While most people will really be enjoying this coming (32) celebration, those of us in the know will be yawning. Everyone else will be (33) for the new millennium and we’ll be saying, "It’s not until next year."
I don’t agree with the (34) , "Ignorance is bliss." But in this case, perhaps it’s (35) .

A:last B:first C:middle D:top

I caught the last bus from town, but Harry came home ______ that night.

A:very late B:even later C:the same late D:the last one

From the last news we do NOT know ______.

A:the results of the two matches B:the number of the teams which played last night C:how many wins the BBS has had altogether D:the Wingers has had one win and four defeats recently

For years, U. S. automakers have fought tougher regulations by arguing that Americans tend to prefer larger, gas-guzzling SUVs and trucks. That’s not always true: when gas prices were at an all-time high last summer, sales of SUVs were down considerably, while hybrids flew off dealer lots. Since then, prices at the pump have dropped-and so has the appetite for small cars. As long as the price of gas remains volatile(易变的, 动荡不定的), it’s far from certain that Americans will buy the more efficient cars and trucks the new standards will require automakers to produce. In the long run, though, a gas tax that puts a floor on fuel prices may be the only way to break America’s SUV addiction. But Obama has said he’s not interested. "You need a price signal. Regulations alone won’t do it," says Lester Lave, director of the Carnegie Mellon Green Design Initiative.
Americans’ appetite for SUVs dropped when

A:gas prices hit new high last summer. B:hybrids were out of stock last summer. C:the government set limits on fuel price last summer. D:the gas price remained fluctuing last summer.