世界上海拔最高的古宫殿群是（）。
A.白金汉宫
B.香利舍宫
C.故宫
D.布达拉宫
参考答案：D
You're badly ill. You'd better _____ cold water. [ ]
A. don't drink
B. not to drink
C. to not drink
D. not drink
2Mb/s速率DDF连接器有不平衡式和平衡式两种类型。（）
