由某种确定的原因引起的误差。 A．绝对误差 B．相对误差 C．系统误差 D．偶然误差

血药浓度降至最低有效浓度直至完全从体内消除的时间为（）。

A．潜伏期

B．持续期

C．失效期

D．残留期

E．消除半衰期

南极地区气候严寒的最主要的原因是（　　）

A．四周被寒流包围

B．有巨厚的冰层

C．地处高纬地区

D．高原地形的影响

客户查询时，涉及存折（单）_____等安全校验信息不显示。(五级、四级)

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 child. 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 selfimitation (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 in 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 sound simply because he also uses it at other times for his father, his dog, or

anything else he likes. Playful and 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 of 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

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

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

炉外精炼加热方式分为（）。

A.电阻加热

B.电弧加热

C.吹氮加热

D.吹氧加热