China's sport stars Yao Ming and Liu Xiang _________ Goodwill Ambassadors (亲善大使) for            Shanghai.      [ ]

A. has been named

B. have been named

C. has named

D. have named

糖尿病患者出现糖尿时易出现（）

A.代谢性酸中毒

B.代谢性碱中毒

C.呼吸性酸中毒

D.呼吸性碱中毒

E.混合性酸中毒