—Not getting that job was a big let-down.

—Don’t worry. Something better will ____.

A．come along

B．take on

C．go by

D．fall behind

检测某动物组织细胞，发现有机物的分解缓慢，酶的催化效率极低。则该细胞正在（）

A.分化

B.分裂

C.癌变

D.衰老