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

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