下列运算中,正确的是( )
A:x2+x3=x5
B:(x2)3=x6
C:2x3÷x2=x
D:2x﹣1=12x
— . The old man who sat here will be back soon.
下列不属于遗传病的是( )
我国以煤炭发电为主,形成这些煤的植物类群主要是古代的( )
—Have you ever seen Zhou Libo’s talk show?—Yes. It's very funny and it often makes people .