问题 选择题

下列说法正确的是

A.电离时生成的阳离子全部是氢离子的单质叫做酸

B.只有酸电离时,阳离子才是氢离子

C.电离时生成的阴离子全部是氢氧根离子的化合物叫做碱

D.所有的盐电离时都生成金属离子和酸根离子

答案

答案:C

电离时生成的阳离子全部是氢离子的化合物叫做酸,A不正确。硫酸氢钠也能电离出氢离子,B不正确。D不正确,例如氯化铵等铵盐,答案选C。

阅读理解

阅读理解。

     Language learning begins with listening. Children are greatly different in the amount of listening

they do before they start speaking, and later starters are often long listeners. Most children will

"obey" spoken instructions some time before they can speak , though the word " obey" is hardly

accurate as a description of the eager and delighted cooperation usually shown by the children.

Before they can speak, many children will also ask questions by gesture and by making questioning

noises.

     Any attempt to study the development from the noises babies make to their first spoken words

leads to considerable difficulties. It is agreed that they enjoy making noises, and that during the first

few months one or two noises sort themselves as particularly expressive as delight, pain, friendliness,

and so on. But since these can't be said to show the baby's intention to communicate, they can hardly

be regarded as early forms of language. It is agreed, too, that from about three months they play with

sounds for enjoyment, and that by six months they are able to add new words to their store. This

self-imitation(模仿) leads on to deliberate(有意的) imitation of sounds made or words spoken to

them by other people. The problem then arises as to the point at which one can say that these imitations

can be considered as speech.

     It is a problem we need to get out teeth into. The meaning of a word depends on what a particular

person means by it a particular situation; and it is clear that what a child means by a word will change

as he gains more experience of the world. Thus the use, at seven months, of "mama" as a greeting for

his mother cannot be dismissed as a meaningless imitation of what other people say continues after the

child has begun to speak for himself. I doubt, however, whether anything is gained when parents take

advantage of this ability in an attempt to teach new sounds.

1. Before children start speaking______.

A. they need equal amount of listening

B. they need different amounts of listening

C. they are all eager to cooperate with the adults by obeying spoken instructions.

D. they can't understand and obey the adult's oral instructions.

2. Children who start speaking late___________.

A. may have problems with their listening

B. probably do not hear enough language spoken around them

C. usually pay close attention to what they hear

D. often take a long time in learning to listen properly

3. A baby's first noises are ________.

A. an expression of his moods and feelings   B. an early form language

C. a sign that he means to tell you something   D. an imitation of the speech of adults

4. The problem of deciding at what point a baby's imitations can be considered as speech_______.

A. is important because words have different meanings for different people

B. is not especially important because the changeover takes place gradually

C. is one that should be properly understood because the meaning of words changes with age

D. is one that should be completely ignored because children's use of words is often meaningless

5. The speaker implies__________.

A. parents can never hope to teach their children new sounds

B. children no longer imitate people after they begin to speak

C. children who are good at imitating learn new words more quickly

D. even after they have learnt to speak, children still enjoy imitating

填空题