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6. Jane’s pale face suggested that she    ill, and her parents suggested that she    a medical examination.

A. be; should have  B. was; have  C. should be; had  D. was; has(上海94)

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5.   it rain tomorrow, we would have to put off the Yangpu Bridge.

 A. Were    B. Should    C. Would    D. Will(上海94)

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4. - I stayed at a hotel while in New York.

- Oh, did you? Oh, I    with Barbara.

     A. could have stayed       B. could stay 

 C. would stay          D. must have stayed(MET98)

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3. You didn’t let me drive. If we    in turn, you    so tired.

A. drove ; didn’t get      B. drove ; wouldn’t get

C. were driving ;wouldn’t get  D. had driven ; wouldn’t have got(MET95)

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2. When a pencil is partly in a glass of water, it looks as if it   .

 A. breaks   B. has broken  C. were broken  D. had been broken(MET95)

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1. I didn’t see your sister at the meeting. If she   , she would have met my brother.

 A. has come   B. did come   C. came   D. had come(MET94) 

试题详情

2.be anxious about = be worried about 为……担忧

     eg: Some people are anxious about the future.有些人对前途感到不安。

  (辨析)anxious和eager 都有“渴望”“急于”的意思,但用法略有不同,anxious 着重指焦急、着急或担心,eager 着重指对成功的期望或进取的热情。

    eg.1. We are anxious to arrive home before dark.

        我们急于在天黑之前到家。

    eg.2. We are eager to join the army.我们渴望参军。

They are more willing to take risks….
    他们更愿意冒险。

 [点拨]take/run risks/a risk意为“冒险”

   eg: She’s too sensible to take a risk when she’s driving.

       她在开车时很有判断力而不致冒险。

    Take/run risk of doing sth冒险做某事:冒……之险

   eg: He was ready to run/take the risk of being taken prisoner by the enemy.

       他愿意冒被敌人俘虏的危险。

If they were not, they wouldn’t be ready to experiment with new forms and to make mistakes, all of which contribute to their increased ability to learn.
如果他们不自信,他们不会愿意去尝试新的形式去出错,而只有尝试新的事物及错误的纠正才有助于学习能力的提高。

 [点拨]experiment with  试验,试用

  eg.1. In order to discover the crops most suited to the soil, they experimented with various kinds of grain.

      为了发现最适合土壤的庄稼,他们试验了各种谷物。

  eg.2.  That man is experimenting with dyes to get the color he wants.

      那人正用染料做试验想要获得他所想要的颜色。

[点拨]contribute to 用法小结

eg.1捐赠、捐助contribute to the Red Cross 捐助红十字会

eg.2 有助于,促成Drink contribute to his ruins.饮酒促成了他的毁灭。

eg.3投稿于:Mr. Green has contributed poems to the London Magazine for several years.格林先生向《伦敦杂志》投诗稿已有几年了。

Not all of us want to be translators or interpreters.

    并不是每个人都想成为一个翻译者或口译者。

Grammar

I have piles of homework to do, therefore I can’t relax.
我有许多作业要做,因此,我无法放松。

[点拨]piles of  意为“一堆堆的,成堆的”

   eg: a pile of books一堆书 piles of books 一堆堆的书

    pile亦可用作动词,词组pile up意为“累积”“堆积”

   eg: My work keeps piling up.我的工作越积越多。

Most exchange students say that they feel as if they were truly part
of their host families and that they will always stay in touch. 许多交流学生说他们觉得他们真正成了房东家庭的一员而且他们将永远保持联系。

[点拨]此句中that they feel…and that they will…in touch 构成谓语say 的并列宾语从句,其中第二个that 在句中不可省略。

[点拨]stay in touch = keep in touch 意为“保持联系”,touch 后常与介词with 搭配意思为“与……的联系”。

与touch 构成的其他短语有:be in touch with 和……有联系 be/get out of touch with 脱离、失去联系 bring…in touch with 使接触,使认识 get in touch with 和……取得联系 lose touch with 与……失去联系

What’s perhaps the most valuable is what you learn about yourself and your own culture.
可能最重要的便是你对自身和所属文化的了解。

[点拨]名词性从句what is…以及what you …own culture分别充当主语和表语从句,其中what可以理解成something that.

   eg: Our hometown isn’t what it used to be.我们的家乡不再是过去的样子。

  Integrating skill

 Many language learners think that the best way to learn a language is to spend time in a country where the language is spoken.许多语言学习者认为学语言最好的方式就是去在讲这种语言的国度里呆上一段时间。

[点拨]1.这是一个长句,主句为many language learners think that…,在that 引导的宾语从句中,the best way 作主语,to learn a language 作the best way 的定语,to spend time in a country 作宾语从句中的表语,where the language is spoken 作 a country 的定语从句。

[点拨]2.关系副词where 引导的定语从句,where 相当于in which 或at which在定语从句中充当地点状语。

  eg.1. The factory where his father works is in the west of the city.

他父亲工作的工厂在城市西边。

eg.2. This is the house where we lived last year.

      这是我们去年住的房子。

Many school offer exchange program at various academic levels at a reasonable cost.许多学校提供价格合理的不同学术层次的交流计划。

 [点拨]at…a level意为“以……水平”又如:consultations at cabinet level 内阁阁员间的磋商

[点拨]at…a cost 以……为代价、以……的价格

   eg.1. to sell sth at cost 照成本卖

   eg.2. The battle was won at (a) great cost in human lives.

        牺牲了许多士兵的性命才换来的这场战役的胜利。

     又如固定搭配:at all costs 不惜任何代价,无论如何

at the cost of牺牲,丧失

     eg: He saved his son from drowning, but only at the cost of his own life.

        他救了他儿子的命:幸免于溺死,但却牺牲了他自己的命。

…it is also possible that some of them may fall behind in their studies.
一些学生有可能在学习上会落到后面。

[点拨]It is possible that…为固定句型,其中possible也可以用likely替换,意思为“有可能……”。此句型还可用sb be likely to do sth…句型替换。但不可以说sb be possible to do sth.

  eg: It’s likely/possible that he will do very well.

         他有可能会干得很出色。

[点拨]fall behind意为“落在后面”

   eg: Soon he fall behind in the race.

比赛不久,他就落在了后面。

     He didn’t want to fall behind in his studies.

他不想在学习上落到了别人的后面。

Grammar

虚拟语气(The Subjunctive Mood)表示说话人所说的话不是事实,而是一种假设、愿望、怀疑或推测。虚拟语气主要用于条件从句、让步从句和名词性从句中。

(1)   虚拟语气在条件从句中的用法:

条件从句
条件从句的谓语形式
主句的谓语形式
表示现在情况
If I(you, he /she, we, they)
 +动词过去式
should/would/could/might
+动词原形
表示过去情况
If I(you, he /she, we, they)
+had+过去分词
should/would/could/might
+have+过去分词
If I(you, he /she, we, they)
+动词过去式
 
 
 
表示未来情况
 
If I(you, he /she, we, they)
+should+动词原形
should/would/could/might
+动词原形
If I(you, he /she, we, they)
+ were to +动词原形
 
 

根据下面例句进一步理解:

①   与现在事实相反:

If I were you, I should do it in another way.

 如果我是你的话,我会用另一种方法做。

②   与过去事实相反:

If I had not studied hard , I would have failed in the exam.

  假如我学习不那么刻苦,就不会通过那次考试了。

③   与将来事实相反:

If you missed(were to miss/should miss)the film tonight, you would feel sorry for it.假如今晚错过了这部电影,你将会感到遗憾的。

(2)   虚拟语气在宾语从句中的用法:

①在wish后面的宾语从句中,谓语常用过去式来表示现在的情况,用过去完成时表示过去的情况,用would/could/might + 动词原形来表示将来的情况。如:

I wish that she were here with me and that we weren’t sick.

I wish I had sent the old man to hospital in time.

I wish I could be with you for the next three months.

would rather, as if, it’s time…, what if,  if only也有类似用法

②在demand, suggest, order, propose, request, command, insist等动词后的宾语从句中,谓语通常用should + 动词原形或只用动词原形来表示愿望、建议、命令、请求等。

She suggested we (should) leave early.

The teacher insisted that the students (should) have a test.

考题档案

试题详情

1.be anxious to do sth(for sth)急于/渴望干某事或得到某物

     eg.1. They are anxious to know the result.他们急于知道结果。

     eg.2. The boy was anxious for a new pen.那个男孩渴望有一支新钢笔。

试题详情

0.064g    x 

 x=0.002mol  [H+]= =4×10-3mol/L

答案:A

[例2]某碱性蓄电池在充电和放电时发生的反应为:

 Fe+NiO2+2H2O Fe(OH)2+Ni(OH)2,下列说法中正确的是:

 A、放电时,负极上发生反应的物质是Fe.

 B、放电时,正极反应是:NiO2+2e-+2H+=Ni(OH)2

 C、充电时,阴极反应是:Ni(OH)2-2e-+2OH-=NiO2+2H2O

 D、充电时,阳极附近pH值减小.

解析:根据原电池在放电时,负极发生氧化反应,正极发生还原反应,再根据元素化合价变化,可判断该电池负极发生反应的物质为Fe,正极为NiO2,此电池为碱性电池,在书写电极反应和总电池反应方程式时不能出现H+,故放电时的电极反应是:负极:Fe-2e-+2OH-=Fe(OH)2,正极:NiO2+2e-+2H2O=Ni(OH)2+2OH-。原电池充电时,发生电解反应,此时阴极反应为原电池负极反应的逆反应,阳极反应为原电池正极反应的逆反应,由此可判断正确选项应为A、D。

答案:AD

[例3]甲、乙两个容器中,分别加入0.1mol/LNaCl溶液与0.1mol/LAgNO3溶液后,以Pt为电极进行电解时,在A、B、C、D各电极上生成物的物质的量之比为:_____________

 

解析:此装置相当于两个电解槽串联到一起,在整个电路中电子转移总数相等.首先判断各极是阳极还是阴极,即电极名称,再分析各极发生的反应.A极(阴极)反应:2H++2e-=H2↑,B极(阳极)反应:2Cl--2e-=Cl2↑;C极(阴极)反应:Ag++ e- =Ag;D极(阳极)反应:4OH--4e-=2H2O+O2↑,根据电子守恒法可知,若整个电路中有4mol电子转移,生成H2、Cl2、Ag、O2的物质的量分别为:2mol、2mol、4mol、1mol因此各电极上生成物的物质的量之比为:2:2:4:1。

答案:2:2:4:1

[例4]有三个烧杯,分别盛有氯化铜,氯化钾和硝酸银三种溶液;均以Pt作电极,将它们串联在一起电解一定时间,测得电极增重总和2.8克,这时产生的有色气体与无色气体的物质的量之比为

 A、4:1  B、1:1  C、4:3  D、3:4

解析:串联电路中,相同时间内各电极得或失的电子的物质的量相同,各电极上放出气体的物质的量之比为定值。不必注意电极增重是多少。只要判断出生成何种气体及生成该气体一定物质的量所得失电子的物质的量,就可以通过电子守恒,判断气体体积之比,第一个烧杯中放出Cl2 ,第二烧杯中放出Cl2和H2,第三烧杯中放出O2。在有1mol电子转移下,分别是0.5 mol,0.5 mol0.5 mol和0.25mol所以共放出有色气体0.5+0.5=1(mol)(Cl2),无色气体0.5+0.25=0.75(mol)(O2和H2)

答案:C

试题详情

8.电解原理的应用

A、电解饱和食盐水(氯碱工业)

  ⑴反应原理

阳极:           

  阴极:            

总反应:2NaCl+2H2O电解====H2↑+Cl2↑+2NaOH 

  ⑵设备 (阳离子交换膜电解槽)

①组成:阳极-Ti、阴极-Fe

②阳离子交换膜的作用:它只允许阳离子通过而阻止阴离子和气体通过。

⑶制烧碱生产过程 (离子交换膜法)  ①食盐水的精制:粗盐(含泥沙、Ca2+、Mg2+、Fe3+等)→加入NaOH溶液→加入BaCl2溶液→加入Na2CO3溶液→过滤→加入盐酸→加入离子交换剂(NaR)   ②电解生产主要过程(见图20-1):NaCl从阳极区加入,H2O从阴极区加入。阴极H+ 放电,破坏了水的电离平衡,使OH-浓度增大,OH-和Na+形成NaOH溶液。

B、电解冶炼铝

⑴原料:(A)、冰晶石:Na3AlF6=3Na++AlF63-

(B)、氧化铝: 铝土矿 eq \o(\s\up 4(NaOH--→ NaAlO2  eq \o(\s\up 4(CO2--→  Al(OH)3 △-→  Al2O3 

⑵ 原理  阳极            

阴极            

总反应:4Al3++6O2ˉ电解====4Al+3O2

⑶ 设备:电解槽(阳极C、阴极Fe) 因为阳极材料不断地与生成的氧气反应:C+O2 → CO+CO2,故需定时补充。

C、电镀:用电解的方法在金属表面镀上一层金属或合金的过程。

⑴镀层金属作阳极,镀件作阴极,电镀液必须含有镀层金属的离子。电镀锌原理:

阳极  Zn-2eˉ = Zn2+

阴极  Zn2++2eˉ=Zn

⑵电镀液的浓度在电镀过程中不发生变化。⑶在电镀控制的条件下,水电离出来的H+和OHˉ一般不起反应。⑷电镀液中加氨水或 NaCN的原因:使Zn2+离子浓度很小,镀速慢,镀层才能致密、光亮。

D、电解冶炼活泼金属Na、Mg、Al等。

E、电解精炼铜:粗铜作阳极,精铜作阴极,电解液含有Cu2+。铜前金属先反应但不析出,铜后金属不反应,形成 “阳极泥”。

试题枚举

[例1]将两个铂电极插入500mL CuSO4溶液中进行电解,通电一定时间后,某一电极增重0.064g(设电解时该电极无氢气析出,且不考虑水解和溶液体积变化),此时溶液中氢离子浓度约为

 A.4×10-3mol/L  B.2×10-3mol/L  C.1×10-3mol/L  D.1×10-7mol/L

解析:根据电解规律可知阴极反应:Cu2++2e-=Cu,增重0.064gCu,应是Cu的质量,根据总反应方程式:

 2CuSO4+2H2O 2Cu+O2↑+2H2SO4--->4H+

       2×64g   4mol

试题详情


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