问题 选择题

下列说法错误的是

A.1个 C3H8分子中的共价键总数为10

B.除去苯中含有的少量溴可以加入NaOH溶液,然后蒸馏出苯

C.可用溴的四氯化碳溶液除去丙烷中的丙烯

D.某聚乙烯单链分子的相对分子质量为519766,则该聚乙烯单链分子的聚合度为19991

答案

答案:C

1个C3H8分子中有8个碳氢键和2个碳碳键,共10个,A项正确;除去苯中含有的少量溴可以加入NaOH溶液,NaOH溶液与溴反应生成盐,苯不与NaOH溶液反应,然后蒸馏出苯,B项正确;丙烷因易溶于四氯化碳而不能用溴的四氯化碳溶液除去丙烷中的丙烯,C项错误;聚乙烯单链分子的相对分子质量为519766,—CH2—CH2—原子团的相对分子质量为26,519766/26=19991,D项正确。

完形填空

“Imagine you are walking along the road. Suddenly you fall over and all the passers-by burst into laughter. You feel very  1  and think the world is laughing at you . But in fact, five minutes later, they have  2   it ever happened.” The other day when I came across these words in an article, I didn’t agree with the  3  .
The author thinks the best thing to do in this kind of  4 is to pretend nothing has happened, and so avoid  5  trouble.
I admit that we should keep  6  because “Your tears will only remind others of what happened, while your  7  can let them forget it.” But this is far from satisfactory. We should do 8  to make things better.
I used to be a(n)  9  girl and not very good at maths. Our new maths teacher asked me a question and I still remember how I hung my head in  10  when I couldn’t answer it.
“If you don’t know the answer, just tell me.” the teacher said, “If you don’t how can I know   11  you know the answer or not?” All of my classmates burst into laughter. My face turned red but the teacher  12  me to go to the blackboard and  13  what I knew. If I had  14  the words in the article, I would have given up. But I tried my best. And to everyone’s  15 , I succeeded! The teacher smiled and said, “Well done! I  16  you could do it!”
Since then, I have become active in maths as  17  as in other subjects. I used to think doing maths exercises was a waste of time. But now, I know  18  I do can make things better. Everyone is the  19  of his own fate.
If we make mistakes, we should take on an active 20  . Laugh, and the world laughs with you; weep(哭泣), and you weep alone.
小题1:
A.nervousB.excited C.afraid D.embarrassed
小题2:
A.realizedB.recognized C.forgotten D.remembered
小题3:
A.speaker B.reader C.author D.announcer
小题4:
A.environmentB.surroundingC.condition D.situation
小题5:
A.ordinaryB.extra C.common D.usual
小题6:
A.confident B.smart C.calm D.strong
小题7:
A.smile B.worry C.courageD.satisfaction
小题8:
A.anything B.something C.nothingD.everything
小题9:
A.shy B.energeticC.happy D.clever
小题10:
A.joy B.prideC.shame D.surprise
小题11:
A.what B.that C.when D.whether
小题12:
A.forced B.invited C.asked D.pushed
小题13:
A.bring upB.put downC.think about D.show off
小题14:
A.obeyed B.doubted C.refused D.understood
小题15:
A.expectation B.disappointment C.surprise D.delight
小题16:
A.hoped B.knew C.doubtedD.regretted
小题17:
A.long B.far C.soon D.well
小题18:
A.whoever B.wheneverC.wherever D.whatever
小题19:
A.architect B.owner C.host D.controller
小题20:
A.position B.attitudeC.value D.response
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