问题
单项选择题
关于毒性下列说法中不确定的是
A．毒性的大小和外源化学物与机体接触途径有关
B．剂量是影响毒物毒性作用的关键
C．毒物毒性的大小与半数致死剂量 LD50值呈正比
D．是指外源化学物对机体造成损害的能力
E．毒性较高的物质，只要相对较小的数量，即可对身体造成损害
答案
参考答案：C
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关于毒性下列说法中不确定的是
A．毒性的大小和外源化学物与机体接触途径有关
B．剂量是影响毒物毒性作用的关键
C．毒物毒性的大小与半数致死剂量 LD50值呈正比
D．是指外源化学物对机体造成损害的能力
E．毒性较高的物质，只要相对较小的数量，即可对身体造成损害
参考答案：C
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| A teacher started his first job at a primary school and wanted to make a good impression (印象) on the children. When he noticed a boy 1 all by himself, 2 the other children were playing football, he walked up to him and asked, "Are you alright?" The boy told him 3 was fine and the teacher left him. A few minutes later, 4 , he noticed that the boy was still standing alone and had not 5 he other boys. This time, the teacher decided to 6 what was wrong. He came up to the boy again and said, "Hi, are 7 you're not feeling left out? Would you like me to be your friend?" The boy 8 uncomfortable, but after a little hesitation (犹豫), he said, "Maybe". Encouraged by his progress, the teacher asked,"Tell me, 9 are you standing here alone?" "Because," the said with clear anger in his 10 , "I'm the goalkeeper." | ||||
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