单选题
{{B}}Passage One{{/B}}
Gravity is a slippery beast. We don't know how strong it is, how it works or how fast its effects move. But this year we made progress.
October saw the most accurate measurement yet of Newton's gravitational constant(引力常数 ), G, a measure of the strength of the gravitational interaction between two objects. A Swiss team calculated G's value by measuring how the gravitational pull of two huge tanks of mercury affected the weights of test masses.
However, there are discrepancies between measurements of G made in different labs. This year a highly contentious(有争议的) explanation for this was proposed. A group of string theorists proposed that gravity is subtly affected by magnetic fields, and that G should be larger near Earth's poles where the magnetic field is stronger. Sure enough, this fits with the measurements so far. So G's varying values might just be the first proof of the hidden dimensions predicted by string theory.
Equally tantalising is possible evidence for the existence of gravitational waves, the ripples in space-time supposedly caused by abrupt, violent cosmic events. An Italian team reported that two massive aluminium bars, one at CERN(欧洲粒子物理研究所) near Geneva, the other in Italy, had once vibrated in unison(一致)—perhaps as a result of a passing gravitational wave, they suggest.
The claims will be closely scrutinised by gravity researchers in Washington state. They got to turn on a very expensive toy this year. LIGO, one of the biggest scientific instruments ever built. Its twin sets of intersecting 4-kilometre-long laser beams should be very sensitive to any waves. But so far the $400-million machine has not seen anything.
At least one gravitational mystery has (hopefully) been wrapped up this year. when you move something, how long before its new position will affect its gravitational pull on surrounding objects? In other words, what is the speed of gravity? Newton thought the effect instantaneous, but Einstein said it could travel no faster than the speed of light.
Astronomers have finally devised a way to test which one of them was right, based on the way gravity bends radio waves from a distant quasar(类星体). They finished the experiment in September. We don't yet know the answer but our money is on Einstein.
单选题 Why is gravitation considered to be a slippery beast?
【正确答案】 D
【答案解析】第1段中的We don't know how strong it is，how it works or how fast its effects move．说明人们对于引力问题还有许多疑惑。
单选题 What kind of metal did the Swiss team use to calculate the G's value?
【正确答案】 C
【答案解析】这一题属于细节题，第2段第3行提到，“calculated G's value by measuring how the gravitational pull of two huge tanks of mercury affected the weights of test masses”通过测量两个巨大的汞柱如何影响被测物的重量来计算G的价值，由此可知，是利用汞来做实验，所以选C。
单选题 A highly controversial explanation proposed by string theorists is that ______.
【正确答案】 A
【答案解析】第3段第2句话：This year a highly contentious explanation for this was proposed.(今年对这个问题提出了一个颇有争议的解释)之后的句子就是该题解题所需的信息所在。
单选题 The report given by the Italian team might provide evidence that ______.
【正确答案】 C
【答案解析】题干中的关键词是Italian team，利用跳读法在文中找到这两个词所在的句子(第4段第2句)，答案就在该句的perhaps as a result of a passing gravitational wave之中。
单选题 Until now LIGO has ______.
【正确答案】 D
【答案解析】答案可以从第5段的最后一句But so far the $400-million machine has not seen anything中推出。
单选题 From the passage we can infer that ______.
【正确答案】 B
【答案解析】该题属于推断引申题。文中没有直接说明作者的见解，但可以从本文的最后一句话 We don't yet know the answer but our money is on Einstein中推断出本文作者倾向于赞同爱因斯坦的见解。