何谓血液中氧含量？正常人氧含量为多少？

《美国的悲剧》，美国作家____  著，揭露和批判了金钱至上的美国            ，对人的普遍的腐蚀毒害作用。

在保持最佳资本结构的情况下，税后净利润首先要满足投资的需求，然后才向股东分配股利，这种股利政策是：（）

A、剩余股利政策

B、固定股利政策

C、固定股利支付率政策

D、低正常股利加额外股利政策

简述维生素D缺乏性佝偻病的预防。

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.\

He wrote the book The Cat in the Hat at the age of ______.

A．50

B．53

C．56

D．87

《真理的入门》