Where is the school? [ ]
A. There it is.
B. I like the school.
C. It's a school.
答案:A
某校九年级一班体育兴趣小组四位同学的身高(单位:cm)分别为:170,170,166,174,则这四位同学的平均身高为______cm.
利用晶体二级管作为整流元件时,其反向电阻与正向电阻的比值为()时最好。
A.1
B.越大
C.越小
D.0