A:乙炔
B:苯甲醛
C:异戊二烯
D:苯乙烯(CH2=CH—C6H5)
- The storybook is very interesting.
- I agree with you. I ______ it twice already.
关于x的方程x²+mx-2m²=0 的一个根为1,则m的值为( )