What __________ do you like? I like math. [ ]
A. time
B. food
C. class
答案:C
l1与l间的距离是.()
(1)l圆C:(x-2)2+(y-1)2=25的切线且过点M(-2,4);
(2)l1:ax+3y+2a=0与l平行.
司马光,司马迁,司马昭,司马懿哪位出生最早?