[填空题]The central heating system seems to have gone wrong.______ (为什么不叫修理工检查一下呢)

[填空题]The central heating system seems to have gone wrong.______ (为什么不叫修理工检查一下呢)

[填空题]The central heating system has proved__________________(没最初期望的那么有效)

[单项选择]A. They have central heating and air-conditioning systems.
B. They have everything that people need.
C. They are well-planned.
D. Many people live in them.

[单项选择]
Central heating became popular only after the Civil War. Typically, coal-burning furnaces (火炉) fueled the early systems. Natural gas had developed into the leading fuel by 1960. Its acceptance resulted in part from its wide uses. Because it comes primarily from U.S. and Canadian fields, natural gas is also less vulnerable (脆弱的) than oil is to War. Oil remains the most important fuel in a few areas, such as New England.
Electric heating dominates most areas with mild winters and cheap electricity, including the South and the Northwest. It was made popular at least in the South by the low cost of adding electric heating to new houses built with air-conditioning. Bottled gas, which is somewhat more expensive than utility gas, is the fuel of choice in rural areas not served by utility pipelines. Wood is the leading heating fuel in just a few rural counties.
Home heating, which accounts for less than 7 percent of all ene
A. 1978
B. 1960
C. 1997
D. 2000

[单项选择]He is not in the office. He must have gone to have classes, ______
A. didn’t he
B. doesn’t he
C. mustn’t he
D. hasn’t he

[单项选择]Is the News Believable
Unless you have gone through the experience yourself, or watched a loved one’s struggle, you really have no idea just how desperate cancer can make you. You pray, you rage, you bargain with God, but most of all you clutch at any hope, no matter how remote, of a second chance at life.
For a few excited days last week, however, it seemed as if the whole world was a cancer patient and that all humankind had been granted a reprieve (痛苦减轻). Triggered by a front-page medical news story in the usually reserved New York Times, all anybody was talking about — on the radio, on television, on the Internet, in phone calls to friends and relatives — was the report that a combination of two new drugs could, as the Times put it, "cure cancer in two years."
In a matter of hours patients had jammed their doctors’ phone lines begging for a chance to test the miracle cancer cure. Cancer scientists raced to the phones to make sure everyone knew about their rese
A. reduce the size of all tumors.
B. prevent breast cancer.
C. cure various diseases.
D. prevent uterine cancer.