—Oh, he is ______ manager who's pleasant to work with. I mean, it is ______ pleasure to work with him.
A:the; \
B:a; a
C:a; the
D:\; a
下列各组地形名称中,全部位于南方地区的是( )
“m=1”是“直线x+m2y=0与直线x-y=1垂直”的( )
下列命题中真命题是( )