问题 完形填空
完形填空。
     There are about fifteen hundred languages in the world.
     But only a few of them are very __1__.English is one of these.Many,many people use it,not
only in England and the USA,but in other parts of the world.About 200,000,000 speak it as
their own language.It is difficult to say how many people are learning it as a __2__language.
Many millions are trying to do so.
Is it easy or difficult to learn English? Different people may have different __3__.Have you
ever __4__ ads of this kind in the newspapers or magazines?
     "Learn English in six month,or your __5__back..." "Easy and funny? Our records and
tapes __6__ you master your English in a month.From the first day your __7__will be
excellent.Just send..." Of course,it never __8__quite like this.
     The only language that seems easy to learn is the mother tongue.We should remember
that we all learned our own language well when we were __9__.If we could learn English
in the same way,it would not seem so difficult.__10__ what a small child does.He listens to
what people say.He tries what he hears.When he is using the language,talking in it,and __11__
in it all the time,just imagine how much __12__ that gets!
So it is hard to say that learning English is easy,because a good command of English __13__
upon a lot of practice.And practice needs great effort and __14__ much time.Good teachers,
records,tapes,books,and dictionaries will __15__.But they cannot do the student's work for him.
( )1.A.difficult
( )2.A.native
( )3.A.questions
( )4.A.found
( )5.A.knowledge
( )6.A.make
( )7.A.spelling
( )8.A.happened
( )9.A.students
(     )10.A.Imagine
( )11.A.using
( )12.A.time
( )13.A.depends
( )14.A.uses
15.A.do

B.important
B .foreign
B .problems
B .watched
B .time
B .help
B .grammar
B .know
B .children
B .Mind
B .thinking
B .money
B .tries
B .takes
B .work

C.necessary
C.useful
C.ideas
C.noticed
C.money
C.let
C.English
C.seemed
C.babies
C.Do
C.trying
C.language
C.has
C.gets
C.help

D.easy
D.mother
D.answers
D.known
D.English
D.allow
D.pronunciation
D.felt
D.grown-ups
D.Think of
D.practicing
D.practice
D.takes
D.costs
D.master

答案

1-5BBDCC   6-10BDABD    11-15BDABC

选择题
实验题

(10分)维生素C是一种水溶性维生素(其水溶液呈酸性),它的化学式是C6H8O6,人体缺乏这样的维生素能得坏血症,所以维生素C又称抗坏血酸。在新鲜的水果、蔬菜、乳制品中都富含维生素C,例如新鲜橙汁中维生素C的含量在500mg/L左右。十二中某研究性学习小组测定了某品牌软包装橙汁中维生素C的含量,下面是他们的实验分析报告。

(一)测定目的:测定×××牌软包装橙汁中维生素C的含量。

(二)测定原理:C6H8O6+I2 →C6H6O6+2H+2I

(三)实验用品及试剂

(1)仪器和用品(自选,略)

(2)试剂:指示剂_________(填名称,1分),浓度为8.00×103mol·L-1的I2标准溶液、蒸馏水等。

(四)实验过程

(3)洗涤仪器,检查滴定管是否漏液,润洗相关仪器后,装好标准碘溶液待用。

(4)用________________(填仪器名称,1分)向锥形瓶中移入20.00mL待测橙汁,滴入2滴指示剂。

(5)用左手控制滴定管的____________(填部位,1分),右手摇动锥形瓶,眼睛注视___________(1分),直到滴定终点。滴定至终点时的现象是________________(2分)。

(五)数据记录与处理

(6)若经数据处理,则此橙汁中维生素C的含量是____________mg/L(2分)。

(六)问题讨论

(7)从分析数据看,此软包装橙汁是否是纯天然橙汁?_______(填“是”或“不是”或“可能是”,1分)。生产商最可能采取的做法是__________(填编号,1分):

A.加水稀释天然橙汁     B.将维生素C作为添加剂    C.橙汁已被浓缩