A:3a+2b='5ab'
B:a﹣a4=a4
C:a6÷a2=a3
D:(﹣a3b)2=a6b2
You ______ go and see a doctor at once because you're got a fever.
下列实验操作中,正确的是( )
车轮要做成圆形,实际上就是根据圆的特征( )