— Must I wait for you here now?     

— No, you ____. You may be back in half an hour. [ ]

A. don't have to

B. mustn't

C. can't

D. shouldn't

对于大气三级评价项目，大气污染源需调查( )

A．评价区工业污染源

B．评价区民用污染源

C．项目工业污染源

D．项目民用污染源