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问题 选择题
下面算式中（　　）运用了乘法分配律．
A．42×（18+12）=424×30B．28×35+28×65=28×（35+65）
C．4×7×5=7×（4×5）
答案

28×35+28×65=28×（35+65），运用了乘法分配律；

故选：B．

问答题

Where one stage of child development has been left out, or not sufficiently experienced, the child may have to go back and capture the experience of it. A good home makes this possible, for example by providing the opportunity for the child to play with a clockwork car or toy railway train up to any age if he still needs to do so. (46)This principle, in fact, underlies all psychological treatment of children in difficulties with their development, and is the basis of work in child clinics.
The beginnings of discipline are in the nursery. Even the youngest baby is taught by gradual stages to wait for food, to sleep and wake at regular intervals and so on. If the child feels the world around him is a warm and friendly one, he slowly accepts its rhythm and accustoms himself to conforming to its demands. (47)Learning to wait for things, particularly for food, is a very important element in upbringing, and is achieved successfully only if too great demands are not made before the child can understand them.
Every parent watches eagerly the child’s acquisition of each new skill — the first spoken words, the first independent steps, or the beginning of reading and writing. (48)It is often tempting to hurry the child beyond his natural learning rate, but this can set up dangerous feeling of failure and states of anxiety in the child. This might happen at any stage. A baby might be forced to use a toilet too early; a young child might be encouraged to learn to read before he knows the meaning of the words he reads. (49)On the other hand, though, if a child is left alone too much, or without any learning opportunities, he loses his natural zest for life and his desire to find out new things for himself.
Learning together is a fruit source of relationship between children and parents. By playing together, parents learn more about their children and children learn more from their parents. Toys and games which both parents and children can share are an important means of achieving this co-operation. Building-block toys, jigsaw puzzles and crossword are good examples.
Parents vary greatly in their degree of strictness or indulgence towards their children. Some may be especially strict in money matters; others are severe over times of coming home at night, punctuality for meals or personal cleanliness. (50)In general, the controls imposed represent the needs of the parents and the values of the community as much as the child’s own happiness and well-being.
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单项选择题

女性，8岁。外伤冠折，切角缺损。口腔检查：缺损处已露髓，探痛（），叩痛（+），无松动。

治疗首选（）

A．直接盖髓术

B．牙髓切断术

C．拔髓术

D．根管治疗

E．塑化治疗
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