I couldn't help applauding for Liu Xiang's excellent performance ________ he got the first prize on the

stage in the 16th Asian Games.[ ]

A. for the first time  

B. suddenly

C. the moment  

D. once

制定加油站数质量应急预案，同一座加油站24小时内连续发生（）起以上同质客户数质量投诉，应立即停止加油作业，启动应急预案。

A.3

B.2

C.5

D.4