UNIT 21
　　Like most parents, geologist Brain Atwater worries about his daughter’s safety. But these days, he has an unusual concern; The public school she 11 in Seattle has unreinforced brick walls, a 12 being easy to collapse during earthquakes. The same 13 of walls crushed hundreds of thousands of people during the 1976 Tangshan quake in China.
　　 A decade ago, Atwater would have paid little notice to schoolroom walls. But over the last several years, he and other scientists have found 14 signs that the Pacific Northwest has experienced giant quakes in the distant past and that the area may be headed for a destructive shock in the near future.
　　At a meeting of the American Geophysical Union in December, researchers discussed the 15 uncovered evidence of quake potential in the Pacific Northwest. While some remain unconvinced that huge earthquakes—with magnitudes of 8 or higher—do indeed 16 this region, a growing number consider such shocks a serious possibility.
　　What’s worrisome, they say, is that northwestern cities such as Portland, Seattle and Vancouver have not prepared for earthquakes of this magnitude, which could shake the region’s 17 centers with enough force to make the recent San Francisco area damage seem 18 in comparison.
　　"I think it’s quite true to say that nothing has really been designed with one of these earthquakes in mind," says seismologist Paul Somerville of Woodward. At the meeting, Somerville and his colleagues 19 estimates of the degree of shaking. Portland and Seattle would suffer during such a 20 earthquake.

A. massive	B.	recently	C.	construction	D.	displayed
E. relatively	F.	attends	G.	type	H.	strike
I. structure	J.	participates	K.	excessive	L.	mild
M. disturbing	N.	population	0.	presented

買知識，賣知識，就上233考試大！還可以免費賺取現金哦！
·您手頭有好東西嗎？上傳上來和大家一起分享吧！你也可以求購你自己想要的資料。 　　·上傳您的精品資料，可獲得收入，既可在網站上進行消費，也可提取現金。 　　·若被評為資料，還可以增加任務分值。了解更多>>

　　編輯推薦：
　　2012年12月大學英語四級報名時間
　　2012年12月英語四級考試時間及流程