下列计算正确的是( )
A:a2•a3=a6
B:2a+3a=6a
C:a2+a2+a2=3a2
D:a2+a2+a2=a6
区别古今词义:
⑴汤:____ ⑵臭:____
I'm sorry to say that I didn't ________ him to become a successful writer.