A:一定浓度的肝素
B:一定浓度的ATP
C:一定浓度的葡萄糖
D:一定浓度的血清
若直线x+ay+1=0与直线x+2y+3=0平行,则实数a=( )
对下列实验事实的解释正确的是( )
- Would you like to attend the farewell party next week, Mr. Huang?
- Sure, I'd love to. I have no reason to _______ your invitation,