单选题Why do many of the boys avoid certain instruments?

单选题BTEXT A/B 1 In the second half of the 20th century, the world became, quite literally, a darker place.2 Defying expectation and easy explanation, hundreds of instruments around the world recorded a drop in sunshine reaching the surface of Earth, as much as 10 percent from the late 1950's to the early 90's, or 2 percent to 3percent a decade. In some regions like Asia, the United States and Europe, the drop was even steeper. In Hong Kong, sunlight decreased 37 percent.3 No one is predicting that it may soon be night all day, and some scientists theorize that the skies have brightened in the last decade as the suspected cause of global dimming, air pollution, clears up in many parts of the world.4 Yet the dimming trend — noticed by a handful of scientists 20 years ago but dismissed then as unbelievable — is attracting wide attention.5 "There could be a big gorilla sitting on the dining table, and we didn't know about it," said Dr. Veerabhadran Ramanathan, a professor of climate and atmospheric sciences at the University of California, San Diego. "There are many, many issues that it raises."6 Dr. James E. Hansen, director of the NASA Goddard Institute for Space Studies in Manhattan, said that scientists had long known that pollution particles reflected some sunlight, but that they were now realizing the magnitude of the effect.7 "It's occurred over a long time period," Dr. Hansen said. "So it's not something that, perhaps, jumps out at you as a person in the street. But it's a large effect."8 Satellite measurements show that the sun remains as bright as ever, but that less and less sunlight has been making it through the atmosphere to the ground.9 Pollution dims sunlight in two ways, scientists theorize. Some light bounces off soot particles in the air and goes back into outer space. The pollution also causes more water droplets to condense out of air, leading to thicker, darker clouds, which also block more light. For that reason, the dimming appears to be more pronounced on cloudy days than sunny ones. Some less polluted regions have had little or no dimming.10 The dynamics of global dimming are not completely understood. Antarctica, which would be expected to have clean air, has also dimmed.11 "In general, we don't really understand this thing that's going on," said Dr. Shabtai Cohen, a scientist in the Israeli Agriculture Ministry who has studied dimming for a decade. "And we don't have the whole story."

单选题Ms. Green has been living in town for only one year, yet she seems to be ______ with everyone who comes to the store.

单选题I dislike Tom for he is merely a mean and profit- ______ guy. A. merry B. hungry C. cheerful D. pleasant

单选题More than once, I believe everybody else in our company would agree with me ,______him to make such promises but he never made it actually.

单选题We consider ______ she should have left without telling anyone beforehand. A. strange why B. it strange what C. it strange that D. that strange

单选题We passed the examination, ______.A. and so he didB. and neither did heC. and so did heD. but he did

单选题It can be inferred from the passage that which of the following is needed to make the trumpet work?

单选题Roger and his wife was so lucky ______; he almost did not get out of the room when the roof collapsed.[A] to escape[B] to have escaped[C] to be escaped[D] to be escaping

单选题Questions 1 to 3 are based on the following conversation.

单选题What course is the student interested in?

单选题There are fast buses, double-decker buses, air-conditioned or heated buses, ______ a good service.

单选题Their happiness was very ______. A. crisp B. brittle C. delicate D. fragile

单选题Why didn’t the man get a call from her former girl friend?

单选题This reference room is for the______use of graduates of English majors.A. extensiveB. exclusiveC. inclusiveD. intensive

单选题Among all the proposals, it was quite preferable that Mr. Li, a very experienced engineer,______ the task.

单选题Mary ______ that the purchase had been a mistake. However, she didn't.[A] ought to acknowledged[B] ought to have acknowledged[C] should acknowledge[D] should be acknowledging