下面的短文有15处空白,请根据短文内容为每处空白白确定1个最佳选项。 It sounds all wrong-drilling holes in a piece of wood to make it more resistant to knock. But it works because the energy from the blow gets distributed throughout the wood rather than focusing on one weak spot. The discovery should lead to more effective and lighter packaging materials. Carpenters have known (51) centuries that some woods are tougher than others. Hickory(山核桃木), for example, was turned into axe handles and cartwheel spokes (车轮辐条) because it can absorb shocks without breaking. White oak (橡木), for example, is much more easily damaged, (52) it is almost as dense. Julian Vincent at Bathe University and his team were convinced the wood’s internal structure could explain the differences. Many trees have tubular(管状的) vessels that run (53) the trunk and carry water to the leaves. In oak they are large, and arranged in narrow bands, but in hickory they are smaller, and more evenly distributed. The researchers (54) this layout might distribute a blow’s energy throughout the wood, soaking up a bigger hit. To test the idea, they drilled holes 0.65 millimeters across into a block of spruce(云杉), a wood with (55) vessels, and found that (56) withstood a harder knock. (57) when there were more than about 30 holes per square centimeter did the wood’s performance drop off. A uniform substance doesn’t cope well with knocks because only a small proportion of the material is actually (58) . All the energy from the blow goes towards breaking the material in one or two places, but often the pieces left (59) are pristine(未经破坏的). "But instead of the energy being concentrated in one place, the holes provide many weak spots that all absorb energy as they break", says Vincent, "You are controlling the places (60) the wood breaks, and it can then absorb more (61) , more safely". The researchers believe the principle could be applied to any material- (62) example, to manufacture lighter and more protective packaging. That could (63) be used in car bumpers (保险杠), crash barriers and armor for military vehicles, says Ulrike Wegst, (64) the Max Plank Institute for Mental Research in Stuttgart. But she emphasizes that you’d (65) to design the substance with the direction of force in mind. "The direction of loading is crucial", she says.
A. effected
B. beaten
C. slapped
D. affected
第二篇 Oceanography Oceanography has been defined as "the application of all sciences to the study of the sea. " Before the nineteenth century, scientists with an interest in the sea were few. Certainly Newton considered some theoretical aspects of it in his writings, but he was reluctant to go to sea to farther his work. For most people the sea was remote, and with the exception of early intercontinental (大陆间的 ) travelers or others who earned a living from the sea, there was little reason to ask many questions about it, let alone to ask what lay beneath the surface. The first time that the question-" what is at the bottom of the oceans" had to be answered with any commercial consequence was when the laying of a telegraph cable from Europe to America was proposed. The engineers had to know the depth profile(起伏形状)of the route to estimate the length of cable that had to be manufactured. It was to Maury of the LIS Navy that the Atlantic Telegraph Company turned, in 1853, for information on this matter. In the 1840s, Maury had been responsible for encouraging voyages during which soundings(测水深) were taken to investigate the depths of the North Atlantic and Pacific Oceans. Later, some of his findings aroused much. popular interest in his book "The Physical Geography of the Sea". The cable was laid, but not until 1866 was the connection made permanent and reliable. At the early attempts, the cable failed and when it was taken out for repairing it was found to be covered with living creatures, a fact which defied contemporary scientific opinion that there was no life in the deeper parts of the sea. Within a few years oceanography was under way. In 1872, Thomson led a scientific expedition (考察), which lasted for four years and brought home thousands of samples from the sea. Their classification and analysis occupied scientists for years and led to a five-volume report, the last volume being published in 1895. We can infer from the passage that the telegraph cable was built mainly for______.
A. oceanographic studies
B. military purposes
C. business considerations
D. investigating the depths of the oceans