--- How come your father can read books in German?

--- Well, he____on a project with some German engineers for 3 years when he was young.

A．worked

B．was working

C．had worked

D．would work

结肠癌的Dukes临床分期中，错误的是（）。

A.A期：癌局限于肠壁内

B.B期：癌穿透肠壁侵入浆膜和（或）浆膜外，但无淋巴结转移

C.C1期：淋巴结转移仅限于癌肿附近及结肠旁淋巴

D.C2期：癌侵润至肠壁外，伴有锁骨上淋巴结转移

E.D期：已有远处转移或广泛侵及邻近脏器无法切除