A:right; right
B:on the right; right
C:right; on the right
D:right; to the right
已知抛物线y=﹣mx2+4x+2m与x轴交于点A(α,0),B(β,0),且1α+1β=﹣2
下列物质中含有氧分子的是 ____
A.高锰酸钾 B.二氧化碳 C.空气 D.____ .
已知复数z=-2-3i,则它的模z=( )
I arrived_____ my building at around 8:30a.m. _____September 11,2001,