-I think _______ask Tim for some advice.

-_______. Last time when I turned to him, he refused to help.

A．you'd rather; I think so

B．you'd better; I'd rather not

C．you have to; I'd rather not

D．you'd better; I think so

细胞内细胞器的分布和定位主要与下面哪个结构有关（）。

A.微丝

B.微管

C.中间纤维

D.纺锤体

E.以上都不是