以下不属于“公地悲剧”案例的是（）。
A.电网捕鱼
B.占道经营
C.南水北调
D.过度放牧
参考答案：C
In C language，functions are important because they provide a way to（）code so that a large complex program can be written by combining many smaller parts.
A．modify
B．modularize
C．block
D．board
泻白散与苇茎汤均可（）
A.清胃热
B.泻肝火
C.清肺热
D.清心火
E.清热毒
