以下说法正确的的是                             （   ）

A．大猩猩与人类的亲缘关系最近

B．类人猿是人类的祖先

C．进化到人类的根本原因是地形和气候的变化

D．“露西”时代的古人类能制造并使用工具

It’s nearly 5 years since I worked in the company. I _______ in a school.

A．taught

B．was teaching

C．am teaching

D．had been teaching