

7月3日 第一篇6 I6 [, n! `- T% g( H/ M K; v' i
biology 2
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Questions 39-42 Listen to Science Watch, a daily radio program.
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(Welcome to) Word comes from California (when you) of a new weapon (and wore) in the war on household pests. Two (set) scientists working for a firm in Anaheim阿纳海姆, California have developed a method to eliminate insects without using dangerous chemicals. The new poison? (heart) Hot air. % F' m2 j* v4 V. |" I) g! r
5 t( _$ x5 H& |# eThe basic idea is that insects cannot adjust temperatures much above normal. In laboratory experiments, cockroaches蟑螂
! q+ \7 [7 {) C2 C$ zand termites can’t survive much more than a quarter of an hour at 125 degrees Fahrenheit华氏温度, or about 50 degrees centigrade.
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; o1 u7 B3 Y' G( Q( v( zThe new method involves covering a house with a huge tent and filling (in) it with air heated to around 65 degrees centigrade. Hot air is (fostering) forced in, q6 T8 [) d8 ~" h, w* k0 t: p/ f
with (suns) fans鼓风机 and the tent keeps the heating inside the house. Since termites try to (skip) escape by hiding in wooden beams, the heat treatment must be continued for a full six hours. But when (that’s) it’s all over and insects (died) are dead, there are no toxic residues to endanger humans or pests and no (found) funny奇怪的 smells.
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Scientists claim that there is no danger of fire either since very few household materials (were) will burn at 65 degrees centigrade. In fact, wood is prepared to construction use by drying it in ovens at 80 degrees centigrade, which is substantially hotter than the air used in this procedure.