The climate change conference has come to __________ end, but the developing countries are

dissatisfied with __________ small step that the developed countries have taken to reduce the

emission (排放) of water gases.[ ]

A. 不填, a          

B. 不填, the      

C. an ,  a          

D. an, the

交叉配血的主要目的是

A.验证血型鉴定是否正确

B.可防止有无张冠李戴

C.防止输血后产生溶血反应

D.验证标准血清是否有误