So  _____ that all the living things died out gradually .

A．serious polluted the lake is

B．serious polluted is the lake

C．seriously polluted the lake is

D．seriously polluted is the lake

无明显抗肿瘤作用的药物是（）

A．黄连 

B．牛黄 

C．苦参 

D．穿心莲 

E．知母