单选题Direction: Read the following text. Choose
the best word or phrase for each numbered blank.
… Earthquake {{U}} {{U}} 1 {{/U}}
{{/U}}can be triggered by many factors, says Tom Hocking, an expert {{U}}
{{U}} 2 {{/U}} {{/U}}earthquake {{U}} {{U}} 3
{{/U}} {{/U}}the California Institute of Technology. The actual {{U}}
{{U}} 4 {{/U}} {{/U}}of quake itself is the breaking {{U}}
{{U}} 5 {{/U}} {{/U}}of rocks at or below the earth's surface. It is
believed by scientists that two of the many reasons are the expansion and
contraction of the earth's {{U}} {{U}} 6 {{/U}} {{/U}}and
continental drift, which are both {{U}} {{U}} 7 {{/U}}
{{/U}}processes. So, finding one all-purpose warning {{U}} {{U}} 8
{{/U}} {{/U}}is impossible. One reason: quakes start deep in the earth, so
scientists can not study them {{U}} {{U}} 9 {{/U}} {{/U}}. If an
early sign of quake is found, it {{U}} {{U}} 10 {{/U}}
{{/U}}still be impossible to warn humans {{U}} {{U}} 11 {{/U}}
{{/U}}of all dangerous quakes. Places like Japan and California are {{U}}
{{U}} 12 {{/U}} {{/U}}with hundreds, if not thousands, of minor
faults. Prediction would be less important if scientists could
easily build structures to {{U}} {{U}} 13 {{/U}} {{/U}}shakes.
While engineering on earthquakes has improved {{U}} {{U}} 14
{{/U}} {{/U}}in the past 10 to 15 years, every new quake reveals new
weaknesses {{U}} {{U}} 15 {{/U}} {{/U}}"quake-resistant"
structures, says an expert at Brown University. In Kobe, for example, a highway
that opened only last year was {{U}} {{U}} 16 {{/U}} {{/U}}. In
the Northridge earthquake, on the other hand, well-{{U}} {{U}} 17
{{/U}} {{/U}}structures generally did not collapse. A recent
report in Science adds yet more anxiety {{U}} {{U}} 18 {{/U}}
{{/U}}life on the faulty lines. Researchers ran computer simulations to see how
quake-resistant buildings would fare in a moderate-size earthquake, taking into
{{U}} {{U}} 19 {{/U}} {{/U}}that much of a quake's energy
travels in a large "pulse" of focused shaking. The results: both steel-{{U}}
{{U}} 20 {{/U}} {{/U}}buildings and buildings that sit on insulating
rubber pads suffered severe damage.