问题
读图填空题
人体发育是从一个细胞开始的，这个细胞是 。
答案
受精卵
题目分析：睾丸产生的精子和卵巢产生的卵细胞都是生殖细胞，卵细胞和精子都不能进行细胞分裂、分化、发育等生命活动．只有精子与卵细胞结合形成受精卵时，才标志着新个体的生长发育的起点．受精卵经过细胞分裂、分化，形成组织、器官、系统，进而形成胎儿．所以人体发育是从一个细胞开始的，这个细胞就是受精卵．
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人体发育是从一个细胞开始的，这个细胞是 。
受精卵
题目分析：睾丸产生的精子和卵巢产生的卵细胞都是生殖细胞，卵细胞和精子都不能进行细胞分裂、分化、发育等生命活动．只有精子与卵细胞结合形成受精卵时，才标志着新个体的生长发育的起点．受精卵经过细胞分裂、分化，形成组织、器官、系统，进而形成胎儿．所以人体发育是从一个细胞开始的，这个细胞就是受精卵．
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| I had been in London for two years. During the time I was 1 there, my strong wish was to 2 instead of staying in the city I didn't know well. So when the day came for my 3 . I had a strange feeling and my mind was full of beautiful things in London-the tall trees around my 4 , the clean streets, the school library, the old church (教堂) near the school and so on. I was for the first time not sure 5 I really wish to go. I was becoming good at spoken English and interested in the different way of living in London. Most important of all. I did not want to leave my 6 who were near and dear to me during the two long years. I felt like running into the head teacher's office and telling him that I really didn't want to go home. But on the second thought I stopped myself 7 the plan. My parents are quite old and I might have no time to see them again if I gave up this plan. At the airport, most of my teachers and friends came to see me off and quite a few gave me 8 . Many group photos were taken and before long the final moment came. Everyone shook hands with me and said goodbye to me. Their eyes 9 tears and I knew they were 10 at the moment. | ||||
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