题目

计算并化简： （1） （2） （3） （4） 答案：解： −110−8÷(−2)2+|−4|×12= −1−8÷4+4×12= −1−2+2=-1； 解： (12−13−512)×(−24)= 12×(−24)−13×(−24)−512×(−24)= −12+8+10= 6 ； 解： 6x2y+xy2−x2y−2x2y= 3x2y+xy2 ； 解： 3(−ab+2a)−(3a−b)+3ab= −3ab+6a−3a+b+3ab= 3a+bIn 1982, Steven Callahan was crossing the Atlantic alone in his sailboat when it struck something and sank. He was out of the sailing track and floating in a lifeboat, alone. His supplies were 1 . His chances of surviving were small. 2 when three fishermen found him seventy-six days later, he was alive — much 3 than he was when he started, but alive.His 4 of how he survived is interesting and attractive. His subtle act — how he 5 to catch fish, how he evaporated sea water to6 fresh water — is very interesting. But the thing that 7 my eye was how he managed to keep himself going when all hope seemed lost, when it seemed no 8 continuing the struggle, when he was 9 greatly, when his lifeboat was pierced and after more than a week’s struggling with his weak body. He was starved and 10 exhausted. Giving up would have seemed the only sensible choice. When people 11 these kinds of circumstances, they do something with their minds that gives them the courage to keep going. Many people in 12 dangerous circumstances give in or go mad. Something the survivors do with their thoughts helps them find the courage to carry on 13 major difficulties. "I tell myself I can 14 it," wrote Callahan in his book. "Compared to what others have been through, I'm fortunate. I tell myself these things over and over, 15 courage and strength." I wrote that down after I read it16 it struck me as something important. And I've told myself the same thing when my own goals seemed17 off or when my problems seemed too powerful. And every time I've said it, I have always come back to my senses. The truth is, our circumstances are only bad 18to something better. But others have been through much worse, that is, in comparison with what 19 have been through, you're fortunate. Tell this to yourself over and over again, and it will help you 20 the rough spots with a little more perseverance(毅力) .1.A.lessB.littleC.fewD.enough2.A.AndB.YetC.StillD.While3.A.thinnerB.poorerC.worseD.fatter4.A.attitudeB.imaginationC.instructionD.story5.A.triedB.tendedC.managedD.intended6.A.makeB.collectC.selectD.replace7.A.attackedB.caughtC.frozeD.cheated8.A.operationB.tasteC.messageD.use9.A.improvingB.sufferingC.strengtheningD.increasing10.A.firmlyB.completelyC.surelyD.generally11.A.dealB.defendC.surviveD.observe12.A.similarlyB.likelyC.probablyD.commonly13.A.for the lack ofB.in spite ofC.in support ofD.as a result of14.A.handleB.carryC.followD.inspect15.A.rolling upB.using upC.building upD.making up16.A.butB.soC.althoughD.and17.A.farB.longC.nearD.short18.A.relatedB.measuredC.contributedD.compared19.A.youB.othersC.weD.another20.A.see throughB.cut throughC.get throughD.think through