环保监测系统的主要功能不包括以下哪项（）
A.环境质量监测子系统
B.视频监控子系统
C.污染源溯源子系统
D.环境监察执法
参考答案：C
法律上的认识错误
—Thank you very much for giving me a hand when I was in trouble.
—Don’t mention it. I only did what anyone else ______ in my place.
A．must do
B．might do
C．would have done
D．can have done
