方程x2-2x=0的根是[ ]
A．x=2
B．x=-2
C．x1=0，x2=2
D．x1=0， x2=-2
答案：C
Does he prefer _______ football to _______ with his online friends? [ ]
A. playing, chat
B. play, chatting
C. playing chatting
D. play, chat
是森林还是农作物对土壤的消耗大，为什么？
