问题
单项选择题 A1型题
甲基汞可通过水体中食物链的作用，使生物体内含量大大高于水体的浓度（）。
A.生物转化
B.生物迁移
C.生物放大
D.氧化作用
E.生物降解
答案
参考答案：C
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甲基汞可通过水体中食物链的作用，使生物体内含量大大高于水体的浓度（）。
A.生物转化
B.生物迁移
C.生物放大
D.氧化作用
E.生物降解
参考答案：C
Bill, a thirteen-year-old boy, thought he had grown up to be a man. But his parents told him, “ You won’t be a real man until you begin to_1_____ helping others.” One morning, his parents gave him some money to 2____ some milk for them. Outside a shop he saw a homeless old man who looked very 3____. Bill went to him and asked, “ What’s wrong with you?” The old man answered, “ I’m hungry. I haven’t had any food for two days.” All the thought of his parents’ words, Bill said to the old man, “Let’s go to the 4_______.” When they got there, Bill asked the waiter to bring out bread and coffee to the old man. The old man finished the meal quickly. After the waiter 5_____the plate and the cup, the old man said, “Sorry for give you too much6_____. I’m fine now. I’ll 7____ forget your kindness! You are a very good young man” Bill was 8______ when he heard this. Just when he wanted to pay for the meal, the waiter came. Bill and the old man learned 9______ that he food was free 10___ it was the birthday of the boss, and they were the first customer(顾客) that day.
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