直线l:y=kx﹣1与曲线C:x2+y2﹣4x+3=0有且仅有2个公共点,则实数k的取值范围是( )
A:(0,43)
B:(0,43
C:{13,1,43}
D:{13,1}
西气东输工程线路的起点是:( )
When I arrived at the office, the meeting ____ (be) on for ten minutes.
____ ____ ____ ____