We must listen to the teacher ________ possible.
A:as careful as
B:as carefully as
C:as more careful as
D:as more carefully as
《未选择的路》中“路”的象征意义是什么?
若a<b<c,则函数fx=x-ax-b+x-bx-c+x-cx-a的两个零点分别位于( )