①陈独秀 ②李大钊 ③鲁迅 ④胡适 ⑤***
A:①②
B:①②③
C:①②③④
D:①②③④⑤
6×7+2____6+2×7 40-3×5____25
(8+16)-4____8+(16-4) 25-4×3____(25-4)+3
73+7-60____30 2×(36-30)____ (36-30)×2
已知直线l:mx+y+3m﹣ 3 =0与圆x2+y2=12交于A,B两点,过A,B分别作l的垂线与x轴交于C,D两点,若|AB|=2 3 ,则|CD|=____.