首页
外语
计算机
考研
公务员
职业资格
财经
工程
司法
医学
专升本
自考
实用职业技能
登录
外语
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 t
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 t
admin
2011-01-05
63
问题
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.
选项
A、If
B、Just
C、Only
D、Rarely
答案
C
解析
本题考查的是连接词的使用。空格所在的句子是一个倒装句,所以应该选only。Only when引起主句中主语和助动词倒置。整个句子的意思是:只有当每平方厘米超过30个孔时,木头抵御敲打的表现才变差。故选C。
转载请注明原文地址:https://kaotiyun.com/show/u9Qd777K
本试题收录于:
职称英语理工类C级题库职称英语分类
0
职称英语理工类C级
职称英语
相关试题推荐
TheGreatNewspaperWarUpuntilabout100yearsago,newspapersintheUnitedStatesappealedonlytothemostseriousread
Jensenisadangerousman,andcanbeverybrutal.
ActiveinOldAgeKeepsPeopleMobilePeopleover70whoaren’tactivearemorelikelytodevelopproblemswalkingorclimbi
Thetiesymbolizesallofthefollowingexcept______.WhendidBritishgentlemenbegintoweartiesregularly?
A.BreakthenewsascalmlyaspossibletochildrenB.BreakthenewsatyourownpaceC.Sharethegoodnewswithyourfriends
Thewayonelooks,talksandmovesdependsBrothersandsistersoftenlookabitdifferentfromeachotherbecause
Mom’sTrafficAccidentsTheybicyclingcrazecameinwhenwewerejustaboutattherightagetoenjoyit.Atfirsteven"sa
Rainmaking1Theideaofrainmakingisalmostasoldasman,butitwasnotuntil1946thatmansucceededinmakingrain.Inanc
OnlyinFebruaryshouldattentionbepaidtochildren’soralhealth.Somechildrenhaveneverseenadentistbeforestartingsc
Atthattime,wedidnotfullygraspthesignificanceofwhathadhappened.
随机试题
积分=____________.
男,51岁。主诉肛周疼痛8天,伴畏寒发热,查肛门旁皮肤红肿,压痛明显,有波动感。考虑患者最可能的状况是
阿托品松弛平滑肌作用强度顺序是
A.知母B.丹皮C.秦皮D.诃子E.六曲上述药物属于曲蘖散组方药物的是
除去中药中鞣质的方法()。
背景资料:某施工单位A承包了二级公路M合同段路面工程。路面结构图如下图所示:施工前,相关单位组织技术人员和管理人员对图纸进行了复核,复核中重点关注了图纸是否符合现行相关技术标准、规范要求,有无重大原则错误;现有施工技术水平能否满足设计
差旅费报销单按填制的手续及内容分类,属于原始凭证中的()。
某税务机关在税务稽查中发现甲企业在增值税专用发票的使用上存在违法行为,在考虑对甲企业进行处罚的过程中,该税务机关主要考虑税收法律对该违法行为的处罚规定,而不考虑该企业对本地财政的贡献。该税务机关的做法符合()。
下列对高中语文教师实施课程要求的解说,不正确的一项是()。
InaBertelsmannFoundationstudyonsocialjusticereleasedthisfall,theUnitedStatescameindeadlylastamongtherich【M1】
最新回复
(
0
)