题目

某植物为自花传粉闭花受粉的二倍体植物，育种工作者用适宜浓度的秋水仙素处理基因型为Aa（A对a完全显性）的该植物幼苗的芽尖，该幼苗部分细胞染色体数目加倍发育成植株（甲），从中选育出子代四倍体品系（乙）。下列相关叙述，正确的是（ ）A.甲植株的根尖细胞中最多含有8个染色体组B.乙植株的体细胞中最多含有8个染色休组C.秋水仙素促进着丝点断裂导致染色体加倍D.自然状态下，甲植株的子一代中隐性个体占1/36The train started moving. There were many people of all ages. Most of them were working men and women and young college boys and girls. Near the window sat an old man with his son, who looked about thirty years old.As the train moved, the son was filled with joy(快乐) because he was very excited at the scenery（风景）outside. He said in a high voice, “See, Dad, the green trees and the scenery are very beautiful!” It made the other people feel very strange. Everyone started talking in a low voice about the old man’s son. A few minutes later it started raining. Raindrops fell on the travelers through the opened window. Seeing the rain, the old man’s son said happily, “See ,Dad, how beautiful the rain is!” Hearing these words, a young lady became angry with the man, as the raindrops were dropping on her new clothes. She shouted at the noisy son and his father. “Can’t you see it is raining? You! Old man! If your son is not feeling well, get him to a mental(精神的) hospital quickly and please don’t disturb（干扰）us any more!” The old man’s face turned red and then he answered in a low voice, “We are on the way back from hospital. He couldn’t see anything at birth. Only last week he could see again. The rain and the nature（自然）are new to him. Please forgive him.” All the other people became quiet.【1】How old was the old man’s son?A. About 7 years old. B. About 20 years old.C. About 50 years old. D. About 30 years old.【2】What did people think of the son at first?A. lovely B. funny C. strange D. clever【3】What was wrong with the son when he was born?A. He had mental illness. B. He couldn’t see.C. He couldn’t hear. D. He couldn’t walk.【4】What is the Chinese meaning of the underlined word ?A. 忘记 B. 谴责 C. 原谅 D. 尊重【5】According to the passage, what does the writer want to tell us?A. We should be friendly to sick people.B. We should learn to enjoy the nature.C. We should respect the elder people.D. We should know the truth before complaining.