题目

受精鸡蛋经过孵化发育成小鸡，此发育过程的基础是①细胞分裂 ②细胞分化 ③细胞休眠 ④细胞衰老 A . ①② B . ①③ C . ②③ D . ③④ 答案：AA man got off the bus and Sam, the bus driver, drove on. Soon the bus to the next stop. old man got on it. “This boy you his seat.”Sam said to the old man. But the boy in the front seat did not move the old man went up to him, Sam looked at him. Then he said again to the old man in a voice,“This boy will be glad to give you his seat.” This time the boy it. His face red. He got up at once. Then the old man sat down said to the boy, “Thank you, my boy.” “Most people want nice,” Sam told the old man. “They just forget that. Sometimes they need a little . I am glad to give them such a push sometimes, too.”1.A. come B. comes C. came D. coming2.A. A B. An C. The D./3.A. will give B. give C. gives D. gave4.A. while B. if C. unless D. when5.A. loud B. louder C. loudly D. loudest6.A. hear B. hears C. heard D. hearing7.A. goes B. go C. went D. gone8.A. and B. so C. but D. or9.A. will be B. to be C. be D. being10.A. rest B. money C. place D. push