【正确答案】
D
【答案解析】[听力原文] Now let's continue our topic. Moving rocks, you may have heard about them. It's quite a mystery. Death Valley is a desert plain, a dry lake bed in California surrounded by mountains and on the desert floor these huge rocks, some of them hundreds of pounds. And they move. But nobody has been able to figure out how they are moving because no one has ever seen it happen. Now there are a lot of theories, but all we know for sure is that people aren't moving the rocks. There are no footprints, no type tracks and no heavy machinery...uh, nothing was ever brought in to move these heavy rocks. So what's going on? Theory No.1—Wind. Some researchers think powerful uh...windstorms might move the rocks. Most of the rocks move in the same direction as the dominant wind pattern from southwest to northeast. But some, and this is interesting, move straight west while some zigzag or even move in large circles. Hmmm...How can that be? How about wind combined with rain? The ground of this desert is made of clay. It's a desert, so it's dry. But when there is the occasional rain, the clay ground becomes extremely slippery. Some scientists theorized that perhaps when the ground is slippery the high winds can then move the rocks. There's a problem with this theory. One team of scientists flooded an area of the desert with water, then try to establish how much wind force would be necessary to move the rocks. And get this: you need winds of at least five hundred miles an hour to move just the smallest rocks! And winds that strong have never been recorded. Ever! Not on this planet. So I think it's safe to say that that issues has been settled. Here is another possibility—ice. It's possible that rain on the desert floor could turn to thin sheets of ice when temperatures drop at night. So if rocks...uh become embedded in ice, uh...OK, could a piece of ice with rocks in it be pushed around by the wind? But there's a problem with this theory, too. Rocks trapped in ice together would have moved together when the ice moved. But that doesn't always happen. There are a few other theories. Maybe the ground vibrates, or maybe the ground itself is shifting, tilting. I bet you are saying to yourself well, why don't scientists just set up video cameras to record what actually happens? Thing is, this is a protected wilderness area. So by law that type of research isn't allowed. Besides, in powerful windstorms, sensitive camera equipment would be destroyed. So all this leads back to my main point—you need to know about more than just rocks as geologists. According to the professor, what have the researchers agreed on? 本录音第一小题选项中重复出现的the rocks和move，以及后两题选项中的reach a conclusion和experiment(s)表明，录音可能与岩石的移动有关，可能涉及一些实验和结论。 选项均为描述the rocks的句子，结合其中重复出现的move，以及cannot，never和in circles可知，本题可能考查岩石的移动方式或特点。 录音中提到，现在有很多关于岩石移动的理论，但我们唯一能确定的是人类没有移动过这些石头，故答案为D。
【正确答案】
A
【答案解析】[听力原文] How does the professor think of the experiments about wind speed and rocks? 选项中的results，carried out，reach a conclusion和experiments表明，本题可能考查某项实验的结果或进展情况。 录音中在谈及风速和岩石的实验时提到，哪怕最小的石头也需要至少每小时五百英里的强风才能被移动，而如此强大的风力还从来没有在地球上出现过。因此他认为该实验已经证明移动岩石的并不是风(that issues has been settled)。由此可知，教授认为这个实验的结果是具有决定性意义的，故答案为A。