试题与答案

根据要求完成下列填空. (1)夏天盛放冰镇啤酒的杯子外壁上附有一层水珠,说明空气

题型:填空题

题目:

根据要求完成下列填空.

(1)夏天盛放冰镇啤酒的杯子外壁上附有一层水珠,说明空气中有__________

(2)发现元素周期律和元素周期表的科学家是 __________

答案:

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下面是错误答案,用来干扰机器的。

(1)C2H6O(1分) 酯基(1分) (2) (1分) (3)加成反应(1分)(4)CH2BrCH2Br+2NaOHHC≡CH+2NaBr+2H2O(2分)(5)CH3CHO(1分)(6) 或、(2分)题目分析:根据F最大荷质比为86,Mr=86,并根据n(C):n(H):n(O)=2:3:1,推...

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题型:完形填空
My best friend, Tom, and I live in a senior-citizen apartment in a lovely small town. Tom is a ten-year-old dog and I am a sixty-nine-year-old lady .
Years ago, I __36__  when I retired I would get a dog to __37__  my golden years. From the very beginning, Tom has always been __38_ and I never have to tell him anything more than once. He is extremely __39___ and always puts back the toys where they were after __40__.He is a wonderful companion. We sometimes play a ___41___together. He does many amusing things that make me laugh. As a result, I enjoy his__42___.
One afternoon, Tom started acting ___43__. I was sitting on the floor playing with him, __44___he started sniffing at the right side of my chest. He had never done anything like this before, suddenly he threw his entire__45__at the right side of my chest, and I cried in___46___.
Soon after this, I felt a lump(肿块). After X-rays and tests, doctors told me I __47__cancer. When cancer started, for an unknown __48___, a wall of calcium(钙化壁) built. Then the lump or cancer _49__ itself to the wall. When Tom __50__on me, the force broke the lump away from the calcium wall, which made me ___ 51__the lump. Before that, I couldn’t see or feel it, so there was no way for me to know it was there.
I had a complete __ 52___ and the cancer did not spread. The doctors told me if the cancer had gone unfound even six more months, it would have been too late.
Was Tom ___53__ of just what he was doing? I’ll never really know. What I do
know is that I’ m glad I made a promise to_ 54 __my golden years with this wonderful creature---- for Tom not only shares his life with me; he has made sure that I will be ___55___to share my life with him.
小题1:
A.suggestedB.insistedC.toldD.promised
小题2:
A.takeB.bringC.shareD.carry
小题3:
A.well-behaved B.well-builtC.well-dressedD.well-known
小题4:
A.dirtyB.neatC.lazyD.sad
小题5:
A.workingB.sleepingC.eating D.playing
小题6:
A.jokeB.funC.gameD.face
小题7:
A.companyB.kindnessC.careD.comfort
小题8:
A.happilyB.luckilyC.strangelyD.sadly
小题9:
A.whileB.whenC.asD.before
小题10:
A.powerB.energyC.devotionD.weight
小题11:
A.joyB.surpriseC.painD.relief
小题12:
A.enjoyedB.hadC.livedD.treated
小题13:
A.causeB.excuseC.reasonD.idea
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A.attachedB.devotedC.fellD.dropped
小题15:
A.jumpedB.satC.stoodD.put
小题16:
A.watchB.witnessC.observeD.notice
小题17:
A.taskB.workC.operationD.job
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A.fondB.awareC.ashamedD.afraid
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A.wasteB.spendC.costD.make
小题20:
A.inB.aroundC.outD.outside
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题型:问答题

如图所示,半径为R=0.2m的光滑

1
4
圆弧AB在竖直平面内,圆弧B处的切线水平.B端高出水平地面h=0.8m,O点在B点的正下方.将一质量为m=1.0kg的滑块从A点由静止释放,落在水平面上的C点处,(g取10m/s2)求:

(1)滑块滑至B点时对圆弧的压力及的OC长度;

(2)在B端接一长为L=1.0m的木板MN,滑块从A端释放后正好运动到N端停止,求木板与滑块的动摩擦因数μ.

(3)若将木板右端截去长为△L的一段,滑块从A端释放后将滑离木板落在水平面上P点处,要使落地点P距O点的最远,△L应为多少?

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