A:GPS
B:GIS
C:RS
D:GPRS
① talk____ ② play____ ③ take____
④ write____ ⑤ walk____ ⑥ draw____
— Which bus do I need _____?
— Bus No. 818.
圆C1:x2+y2+2x+8y-8=0与圆C2:x2+y2-4x-4y-1=0的位置关系是( )