题目

阅读下面材料，在空白处填入适当的内容（只填1词）或括号内单词的正确形式。 One day a rich man took his son on a trip to the country so he could have his son see how poor country people were. They stayed one day and one night in the farm-house of very poor farm. the way back home at the end of the trip the father asked the son, “ did you think of the trip?” The son(reply), “Very nice, Dad.” The father then asked, “Did you notice how poor they were?” The son said, “Yes, I guess so.” The father then added, “What did you learn?” To question, t 下图是蚕豆叶的横切面，据图回答问题。 (1) 注明各部分结构名称： ①________，②________，③________，④________，⑤________，⑥________。 (2) 气体出入的门户是［　　］（填号码）叫________，它是由________细胞控制的。 (3) ［①］和［⑤］的结构特点是：细胞是________的，由________层排列________的细胞构成，外壁上有________，易透光不易透水。