问题 问答题 简答题

简述气相色谱—质谱法测定水中多氯联苯中固相萃取圆盘的活化过程。

答案

参考答案:

圆盘用5m1丙酮浸泡,然后抽干;依次加入1∶1的二氯甲烷和乙酸乙酯混合溶液、甲醇、纯化水,活化圆盘。

完形填空

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第二节完型填空(共20小题;每小题1.5分,满分30分)

阅读下面短文,掌握其大意,然后从36—55各题所给的四个选项(A、B、C和D)中,选出最佳选项,并在答题卡上将该项涂黑。

When I come across a good article in reading newspapers,I often want to cut and keep it.But just as I am about to do so,I find the article on the   31   side is as much interesting.It may be a discussion of the way to   32   in good health,or advice about how to behave and   33  yourself in society.If I cut the front articles,the opposite one is likely to suffer   34  ,leaving one half of it or keeping the text    35    the title.Therefore,the scissors would stay before they start,    36   the cutting would be halfway done when I find out the   37    result.

Sometimes two things are to be done at the same time,both worth your   39   .You can only take up one of them;the other has to wait or be   39   up.But you know the future is unpredictable—the changed situation may not   40   you to do what is left behind.Thus you are   41   in a difficult position and feel sad.How come nice    42  and clever ideas should gather around all at once? It may happen that your life   43    greatly on your preference of your one choice to the other.

In fact that is what   44   is like;we are often   45   with the two opposite sides of a thing which are both  46    like a newspaper cutting.It often occurs that our attention is   47   to the thing only after we get into another.The former may be more important than the latter and this   48   a divided mind.I still remember a philosopher’s   49 :“When one door shuts,another opens in life.”So a casual(不经意的)    50   may not be a bad one.

31.A.same       B.opposite       C.either              D.front

32.A.get          B.bring         C.1ead              D.keep

33.A.enjoy              B.help        C.conduct           D.dress

34.A.damage        B.destroy         C.hurt             D.injury

35.A.on           B.for            C.without           D.off

36.A.or           B.but          C.so               D.for

37.A.satisfying      B.regrettable     C.surprising          D.impossible

38.A.courage        B.patience        C.strength            D.attention

39.A.given       B.picked        C.held               D.made

40.A.persuade       B.agree        C.allow              D.tell

41.A.filled        B.struck       C.caught             D.attracted

42.A.chances        B.conditions     C.wishes          D.ways

43.A.progresses     B.goes          C.changes             D.improves

44.A.study       B.1ife           C.society              D.nature

45.A.supplied       B.connected      C.fixed              D.faced

46.A.available      B.desirable      C.considerable        D.enjoyable

47.A.turned         B.transferred    C.paid             D.drawn

48.A.gives way to   B.gives rise to   C.gets through to     D.gets close to

49.A.remarks       B.sayings        C.slogans            D.comments

50.A.behavior     B.action       C.choice             D.attitude

单项选择题