Only after he had spent several nights working on the math problem to wonder whether the problem was wrongly set． A．did he beginB．he beganC．he did beginD．began he 题目和参考答案——青夏教育精英家教网—

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33．Only after he had spent several nights working on the math problem_______to wonder whether the problem was wrongly set．　　　　

A．did he begin

B．he began

C．he did begin

D．began he

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Besides giving off gases and dusts into the air, humans produce waste that is poured on the environment. Often, this waste produced by major industries and people is harmful to both nature and human life.

One of the main causes of the large amount of dangerous waste is that people do not realize how large a problem it is. Because it can be simply removed and sent to a landfill(废渣填埋场),the problem is often believed to end there. In addition, industries have often shown an unwillingness to find ways to deal with dangerous waste because of the related expenses. Many industries and governments build simple landfills to store waste, and often just pour waste chemicals into nearby bodies of water. Often, chemicals used for industrial production cause dangerous forms of waste.The amount of these chemicals has increased greatly in the past, but it is often difficult and expensive to get rid of these chemicals or to store them in a way safe to human life and the environment.

Every year, major health problems result from dangerous waste. Sadly, it is often only after someone has died or become seriously ill that governments will take measures to reduce levels of harmful waste.

Some governments have realized how serious the dangerous waste problem is and are now trying to settle this problem. They are also trying to limit the amount of waste industries are allowed to produce.

Not only governments but ordinary people as well must work together to solve the problem. They can choose not to buy those products which require the production of dangerous waste, and produce less harmful waste themselves. Many scientists think that waste production can be cut. The waste can be reduced by at least one third using existing technologies and methods.

1.What would be the best title for the text?

A．Measures of Reducing Dangerous Waste

B．Danger of Harmful Waste to Mankind

C．Dangerous Waste and Water Pollution

D．Environmental Protection

2.According to the text, people ________ .

A．do not produce harmful waste in their daily life

B．do not know where to place the dangerous waste

C．are not clear about how serious the dangerouswaste problem is

D．are not sure about where harmful waste ends

3.What troubles industries most in dealing with the dangerous waste problem?

A．How to get government support.

B．How to increase their production.

C．How to store harmful waste.

D．How to cut down the related costs.

4. What can be inferred from the passage?

A．The polluting industries are not allowed to sell their products.

B．Present technologies have settled the harmful waste problem.

C．Everyone should obey the government rules for the problem.

D．To solve the problem requires the efforts of the whole society.

Only after they had discussed the matter for several hours ______a decision.

A．they reached

B．did they reach

C．they reach

D．do they reach

Only after__________ his work __________ to see his grandfather.

A. finishing; did he go B. he finishes; did he go

C. he finished; he went D. having finished; he went

Only after he took off his sunglasses ______ him as one of my favourite movie stars.

A．I recognized	B．I didn’t recognise
C．did I recognize	D．had I recognized

In recent years, an increasing number of teenagers have the problem of obesity（肥胖）. This problem shouldn’t be ignored. It’s harmful disorder that can cause a number of health problems in children.

Many factors in life play an important role in developing obesity among teenagers. Generally, obesity happens when a Person uses more calories than he burns up. A child of fat parents is at higher risk to develop obesity. If both the parents are overweight, then there are 80% chances of developing obesity in children. Also, poor eating habits and lack of exercise can develop obesity in teenagers.

Obesity is a serious condition as it can result in many health problems in any age. Fat children are at greater risk of developing diabetes, high blood pressure, heart diseases and breathing problems. A fat child also shows signs such as daytime sleepiness, morning headache, ete.

In addition to these physical effects, obesity in children causes some serious psychological effects. Fat children car often laughed at by other for their being overweight. It can create a low self-esteem in them. It contributes to poor memory and poor performance at school. Also they hate attending the social events.

Obesity among teenagers can be treated by changing diets, increasing physical activities and taking certain medicine. Foods containing fats and high calories should be strictly removed from their diet. However, you should be careful that teenagers should get enough nutrients required for a healthy growth through their diet. You should make sure the children join in more physical activities and exercise. In some severe cases, the drugs should be given only after seeing the doctor.

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