毒品不仅损害人的中枢神经系统，对血液循环系统、呼吸系统、免疫功能也有影响。[ ]
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介词填空。
1. How much progress _____ English do you think you've made this year?
2. English corners are _____ people _____ a low level _____ English.
3. I'm proud _____ what I've learnt.
4. It's good to practise even if the other person is better than you are _____ English.
5. Do you have difficulties _____ your handwriting?
以下指标中哪项可用来描述计量资料的离散程度（）
A.极差
B.中位数
C.均数
D.几何均数
E.以上均不是
