Across the Deserts

　　The SaharaDesertis the largest desert in the world. It stretches across Africa fromSenegaltoEgypt. TheSaharaDesertis an unfriendly environment. During the day it"s very hot, and at night it’s sometimes very cold. It is also difficult to find water in theSahara.

　　In 2006, Kevin Lin, Ray Zahab, and Charlie Engle decided to do something very difficult. They made the decision to run across the Sahara Desert 4,300 miles (6,920km). It seemed impossible to do, but they wanted to try. The three men liked to test themselves, and this would be a very big test.

　　On the morning of November 2, Kevin, Ray, and Charlie started their trip across theSahara. Every morning they began running at 5:00. At11 a.m. they stopped and rested until 5 p.m. Then they ran again until 9:30 in the evening. Each day they ran about 40 miles (64 km). Every day it was the same thing. They got up and ran. They listened to music on their iPods, and they ran and ran.

　　Kevin, Ray, and Charlie needed to eat a lot of food during their trip. Most people need about 2,000 calories of food each day. Kevin, Ray, and Charlie needed between 6,000 and 9,000 calories every day. That"s a lot of food! They also needed to drink a lot of water.

　　The three men had some problems on their trip, and many times they wanted to quit and go home. It was often very hot (140°F/60°C) during the day, and the heat made them sick. Their legs and feet hurt. Sometimes it was very windy, and they couldn"t see. One time they got lost. But they didn"t quit. After 111 days, Kevin, Ray; and Charlie successfully finished their trip across theSaharaDesert. They hugged each other and put their hands in the water of theRed Sea. Then they ran to a hotel to take a long shower.

　　词汇：

　　Stretch / strɛtʃ / v. 延伸，伸展

　　Calorie / "kælərɪ / n. 卡(路里)，小卡，大卡

　　Quit / kwɪt / v. 停止，放

　　注释：

Each day the men ran for approximately eight hours.

A:Right B:Wrong C:mentioned

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A:Ik2=0.866Ik3 B:I″k2=0.866I″k3 C:Zs2=［（cUn2）2/S″s2］×103 D:Ik2=1.5Ik3

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A:Ip/I″K2

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A:k1、k2的单位是Mpa B:k1、k2是系数，无单位 C:k1、k2和试件数n没有关联 D:k1、k2和试件数n有关联

在Excel中，对于公式IF（K2=K3，"平衡"，"不平衡"）说法正确的是（）。

A:如果K2=K3，则显示“平衡”，否则显示“不平衡” B:如果K2=K3，则显示“不平衡”，否则显示“平衡” C:IF函数的语法为：IF（logical_test，[value_if_false]，[value_if_true]） D:以上说法都不对

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A:L1、L2为同极性端 B:K1、K2为同极性端 C:L2、K2为同极性端 D:L1、K1为同极性端

一般电流互感器上一次测标有L1、L2，二次测标有K1、K2，则下列组合属同名端的是（）。

A:L1、K1 B:L1、K2 C:L2、K1 D:L2、K2

负反馈调节系统，当正向环节K1和反馈环节K2乘积为（），则可以Y=X/K2。

A:K1*K2》1 B:K1*K2《1 C:K1*K2=1 D:K1*K2=0

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A:k1、k2都增大，k1/k2增大； B:k1增大，k2减小，k1/k2增大； C:k1、k2都增大，k1/k2不变； D:k1和k2都增大，k1/k2减小。

可逆反应2NO2N2O4+Q，50℃时平衡常数K1，0℃时平衡常数K2，100℃时平衡常数K3，则K1，K2，K3之间的数量关系是（）。

A:K1＜K2＜K3 B:K1=K2=K3 C:K3＞K2＞K1 D:K2＞K1＞K3