A:①②
B:①③
C:②④
D:③④
在修建公路的土石方爆破中要用到黑火药,黑火药爆炸时反应如下:S+2KNO3+3C=K2S+X+3CO2.其中X的化学式为( )
You had better _________ wine because you have to drive back home.