下列属于化学变化的是( )
A.火药爆炸
B.汽油挥发
C.冰熔化成水
D.水银受热膨胀
答案:A
最高设计时速低于()KM/H车辆不得驶入高速公路。
A.120
B.100
C.70
D.110
If I _______ what the teacher says, I'll go and ask him for help. [ ]
A. won't understand
B. am not understand
C. doesn't understand
D. don't understand