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问题 单项选择题

高分子化合物的毒性主要取决于

A．高分子化合物的分子量
B．高分子化合物本身的特性
C．高分子化合物中所含助剂的品种
D．高分子化合物中所含游离单体的量
E．高分子化合物中所含游离单体的量和助剂的品种

答案

参考答案：E

解析：高分子化合物生产常用单体多为不饱和烯烃、芳香烃及卤代化合物等。同时，在生产过程中，还加入助剂等。这些单体和助剂等多数对人体健康是有影响的。

单项选择题

D


Doctor Seuss was born in 1904. By the middle 1950s, he had become one of the best-loved and most successful children’s book writers in the world. His books are very popular with young readers. They enjoy the invented words and the pictures of unusual funny animals and plants.
In 1954, Life magazine published(刊登) a report about school children who could not read. The report said many children’s books were not interesting. Doctor Seuss ply hoped to help children and decided to write books that were interesting and easy to read. He used words with the same ending sound, like fish and wish. He did not receive training in art. Yet, he drew the pictures for most of his books.
In 1957, Dr. Seuss wrote The Cat in the Hat. He used less than 230 words to write the book and even a six-year-old should be able to read it. It was a fun story and easy to read. Children loved it. Their parents loved it, too. Today it is still one of the stories they like best. The success of The Cat in the Hat made him want to write more books for children. In 1960, he wrote a book using less than fifty words. The book is called Green Eggs and Ham.
In 1984, Doctor Seuss won a Pulitzer Prize (普利策奖). He was honored for the education and enjoyment his books provided American children and their parents.
He died at the age of 87, but his influence remains. Millions of his books have been sold worldwide. People say his books helped change the way American children learned to read. Yet, his books are loved by people of all ages. Doctor Seuss once said. "I do not write for children. I write for people.\

People like his books because the books ______.

A．are cheap and easy to get

B．were written in different languages

C．are easy and interesting to read

D．were written with invented words
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问答题 简答题

矿井瓦斯灾害的防治状况包括哪些条件？
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