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问题 单项选择题

烟草、烟草花叶病毒、草履虫、噬菌体体内的核苷酸种类依次是（）。

A.8、4、8、4

B.4、4、8、4

C.4、4、8、8

D.8、4、8、8

答案

参考答案：A

解析：烟草是真核生物，同时具有DNA和RNA，所以体内含有8种核苷酸（4种脱氧核苷酸和4种核糖核苷酸）；烟草花叶病毒只含有一种核酸——RNA，所以体内含有4种核糖核苷酸；草履虫是真核生物，同时具有DNA和RNA，所以体内含有8种核苷酸（4种脱氧核苷酸和4种核糖核苷酸）；噬菌体是病毒，只含有一种核酸——DNA，所以体内含有4种脱氧核糖核苷酸。故选A

实验题

酷爱化学的小明同学在家里建立了自己的小小化学实验室，下图是他平时收集的部分实验仪器和装置，请填空：

〔１〕仪器①的名称是：　　　　　　　　　　　　　。

〔２〕小明准备用双氧水制取氧气，为便于控制反应速率而获得平稳的氧气流，则他的发生装置和收集装置应选择图中的　　　　(填字母)，反应的化学方程式为　　　　　　　　　　　　　　　　　　　　　　　。

〔３〕小明还设计了一套制取少量蒸馏水的简易装置，他已经选择了Ｂ和Ｃ，则他还需选择　　　　(填字母)。

〔４〕正上高三的姐姐告诉小明可利用图中的A、B、G、I来组装一套实验室制取甲烷的装置，小明据此推测实验室制取甲烷的反应原理应为下列方法中的　　　　(填序号)  ①加热无水乙酸钠和碱石灰的固体混合物 ②常温下碳化铝和水反应  ③CO和H2在催化剂的作用下反应　　④将某些有机物在隔绝空气的条件下发酵

〔５〕小明和小亮还在家里做了如下实验，将过量的Na2CO3溶液滴入到一定量的CuSO4溶液中，有蓝色沉淀物生成。针对蓝色沉淀物的成分，他们展开了探究：       

〖提出猜想〗经过讨论后，他们提出了三种猜想：

猜想一：沉淀物为CuCO3理由是(用化学方程式表示)：　　　　　　　　       

　　　　　　　　　　　　　　　　　　　　　　　　　　　　

猜想二：沉淀物为Cu(OH)2 , 理由：根据Na2CO3溶液的酸碱性可判断Ｎa2CO3 溶液中一定存在着(填离子符号) 　　　　　。     　

猜想三：沉淀物为：                 

〖查阅资料〗CuCO3和Cu(OH)2 均为蓝色固体，不溶于水。受热后均会分解，各自生成对应的两种氧化物。     

〖设计与实验〗小明设计了如下实验方案，并进行了实验：

第一步：将反应后的固液混合物经过滤、　　　　　并晾干后得蓝色固体；

第二步：将下列装置按照　Ａ→Ｂ→Ｃ的顺序连接并进行实验，发现Ｂ中澄清石灰水变浑浊，Ｃ中白色粉末变蓝。于是小明认为猜想三是正确的。　　　　

〖反思与评价〗小亮认为小明得出的实验结论是不科学的，他的理由是：　　　　　　　　　　　　　　　　　　　　　　　　　　　　　　　　。于是小亮提出了他的改进方法：将上图按照　　　　　　　　　　　　的顺序连接并进行实验，若实验现象同上，则猜想三是正确的。
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阅读理解
阅读理解。
     根据短文内容，从短文后的选项中选出能填入空白处的最佳选项。选项中有两项为多余选项。
                                                    How to Do Well in Exams
     Do not underestimate the power of revision in the days and hours before an examination. The closer
you are to the exam, the more chance you have of storing and retaining crucial information. But do not
overdo it. _1_ An effective daily routine can help you through an exam period, so in the days leading up
to your first exam, get into the habit of being up and ready to work by game. It can be a shock to the
system after months of working to your own timetable to be mentally alert at that time if you have not
prepared for it.
     On the day of the exam, have a good breakfast, pack two of everything you need (pens, pencils,
erasers, etc.),then make your way to the examination hall in good time. _2_.
     Once in your seat, simply pause for a few seconds and collect your thoughts. Close your eyes and
take in a few slow, deep breathes to help you relax. When you turn over the test paper, spend a short
period reading through all the instructions and questions, paying particular attention to key verbs such as
"discuss", "compare" and "evaluate"._3_ It is wise always to allow for 10 minutes at the end of the exam
to give yourself time to go back over your answers. Once you have selected the questions you wish to
tackle, begin by attempting the one you think is your strongest. It will give you more confidence when
you see a well-answered question down on paper. Also remember to write clearly, and do not be afraid
to express the unexpected: after all, examiners can get very bored marking stereotypical answers.
     _4_If you do need something else focus on to help collect your thoughts, choose a fixture in the room,
such as the ceiling or anything else that will not allow you to be distracted (分神).
     Finally, once you have finished, never hang around outside afterwards to attend the discussion by
other students._5_
A. Do not arrive too early, though, as other people's anxiety can be contagious (会传染的),
     and you may suffer from undue panic.
B. Try not to be tempted to look at those around you, or at the clock.
C. When you get home, read the examination paper through and look up all the words you
     didn't understand.  
D. Sleep, exercise and relaxation are all just as important.
E. Map out a quick plan of points you wish to make and how much time you should
    spend on each question.
F. Go and have a well-earned rest, then prepare for your next exam
G. Underestimate the test in your mind.
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