A:a2-ab-b2
B:a2+2ab+3
C:a2-2b+b2
D:a2-2a+1
若a< b <0,则ab与0的大小关系是( )
多音字组词
地:dì____、de____
藏:cáng____、zàng____
转:zhuǎn____、zhuàn____
长:cháng____、zhǎng____
重:chóng____、zhàng____