题目内容
因为结构中含有季铵盐结构，不易通过血脑屏障的药物E．
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因为结构中含有二个羟基，难以通过血脑屏障的药物E．
含苯乙烯基的药物E．
Section B
Directions: In this section, you will hear 3 short passages. At the end of each passage, you will hear some questions. Both the passage and the questions will be spoken only once. After you hear a question, you must choose the best answer from the four choices marked A, B, C and D.
听力原文： Many scientists today are convinced that life exists elsewhere in the universe. Life probably much like that on our own planet. As far as astronomers can determine, the entire universe is built of the same matter. (26) They have no reason to doubt that matter obeys the same laws in every part of the universe. Therefore, it is reasonable to guess that other stars, with their own planets, were born in the same way as our own solar system. What we know of life on earth suggests that life will arise wherever the proper conditions exist.
If we suppose that every star in the universe has a family of planets, then how many planets might support life？ (27)First, eliminate those stars that are not like our sun. Next. eliminate most of their planets; they are either too far from or too close to their suns. Then eliminate all those planets which are not the same size and weight as the earth. Finally, remember that the proper conditions do not necessarily mean that life actually does exist on a planet. It may not have begun yet, or it may have already died out.
This process of elimination seems to leave very few planets on which earthlike life might be found. However. even if life could exist on only one planet in a million, (28) there are so many billions of planets that this would still leave a vast number on which life could exist.
(27)
Any good mystery must eventually uncover a villain, and in a recent documentary, "Who Killed the Electric Car？", the filmmakers duly pointed the finger at General Motors. The【C1】______ is not so simple, but there is little doubt that when GM pulled the plug on its EV1 battery-powered car a decade ago, other【C2】______ followed the Giant carmaker's lead.
Yet GM has now 【C3】______ its enthusiasm for electric vehicles — or at least for their close cousins, hybrid cars (混合动力汽车). At the upcoming auto show, the company is expected to【C4】______ a prototype that overtakes existing hybrids，【C5】______ Toyota's Pruis.
Today's hybrids capture energy normally【C6】______ during braking and coasting and use it to power an electric motor that can provide extra bursts of【C7】______ when needed. The Pruis and other hybrids can also run【C8】______ battery power alone at low speeds over short distances, such as in stop-start traffic.
But GM's new car is expected to be a "plug-in" hybrid, which, as its name implied, can be recharged by 【C9】______ it into the mains (干线). Together with a big battery pack, this provides a much larger range in all-electric【C10】______ , after which the petrol engine kicks in. GM's car is expected to go around 50 miles (80 km) in all-electric mode，【C11】______ enough for American commuters, who would need to use the 【C12】______ engine on longer trips only. The【C13】______ is that plug-in hybrids need a much larger and more costly battery pack．【C14】______ a Pirus to operate as a plug-in hybrid, as some enthusiasts have done, costs around ＄12,000.
GM bosses have hinted that his company planned to put a plug-in into mass【C15】______ . It is an indication of how the pace is 【C16】______ in the race to develop more eco-friendly cars.
Others are more【C17】______ . Carlos Ghson, the boss of Renault and Nissan, who is 【C18】______ for his skepticism towards hybrids, said he still had doubts that hybrid technology is【C19】______ for the mass market, stressing that plug-in hybrids will have to wait until battery technology improves. Toyota has also been【C20】______ about plug-ins, insisting the Pims' approach is more convenient.
【C1】
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