下面哪一项不属于外部性公共政策( )
A．政府实施公共交通优先的政策
B．对正外部性给予补贴
C．对负外部性收取费用
D．对住房租金实行改革
参考答案：D
The feeling of competition among the students in all the classrooms where the test was going on was noticeable to everyone.
A．discord
B．discovery
C．rivalry
D．cooperation
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