二氧化碳结合力降低见于（）

A.肺心病呼吸衰竭

B.呼吸性酸中毒

C.代谢性酸中毒

D.代谢性碱中毒

E.正常健康人

He was diagnosed with cancer last month, but he carried on with his work ______ nothing had happened.

A．even thought

B．as if

C．so that

D．in case