—You'd better do more speaking.
A:how I can improve my English
B:which way can I choose
C:how I do with my English
D:what's wrong with my English
“酒驾”已经写入刑法。人体内酒精含量超过20mg/100mL为酒驾,酒精含量超过80mg/100mL为醉驾。交警常用一种“酒精检测仪”检测司机是否酒后驾车。其反应原理为C2H6O + 4CrO3 + 6H2SO4═2X + 2CO2↑+ 9H2O,反应中红色的CrO3转变为绿色的化合物X,则X的化学式为()
如果向东走3m记作+3m,那么向西走8m记作____m.