What is happening in our weather? Of course we have never been able to predict exactly w

What is happening in our weather？ Of course we have never been able to predict exactly what the weather will be like, but now strange weather patterns are seriously affecting many parts of the world. For example, droughts (旱灾) in Mexico and Brazil have recently caused great crop losses and in the United States they have even had to make their own snow for the Winter Olympics!

Scientists have found that the cause of this strange weather is that the air circulation pattern has changed and is now more variable than earlier in the twentieth century. This means that different regions of the world get long spells (持续时间) of the same type of weather, whether hot , cold, wet or windy.

However, weather experts have different views about why this has happened. One theory is that the temperature of the sea has increased. Another is that man’s activities on earth have disturbed the balance of nature.

Whatever the cause, the economics of many countries in the world depend upon the weather. And until we know exactly what effect man’s activities are having on the weather, we cannot make changes which might help. So for the moment the only answer is …wait and see!

26. Which of the following statements is TRUE according to the first paragraph？

A. We have never predicted the weather.

B. Man is now able to control the weather.

C. Strange weather has appeared only in some North American countries.

D. It has always been impossible for man to predict the weather accurately.

27. The strange weather patterns on the earth can he best described as ________.

A. steady and balanced C. likely to cause serious disasters

B. changeable but predictable D. unpredictable but favorable to man

28. The word “affecting” in Paragraph 1 can be replaced by ________.

A. yielding good crops in C. causing few losses in

B. having harmful effects on D. producing desired effects on

29. We can learn from Paragraph 2 that ________.

A. weather patterns are similar in different regions of the world

B. the air circulation pattern remains unchanged in the last century

C. our weather depends on the changes in the air circulation pattern

D. it is possible to predict weather patterns over a long period of time

30. It can be learned from this passage that ________.

A. scientists have similar opinions about the changing weather

B. no one is sure about the cause of the changing weather

C. cutting down forests has affected the climate

D. the weather will become worse in the future