Leave your key with your neighbor      you lock yourself out one day.

A． as long as

B． even though

C． in case

D． as if

环境影响是指( )对环境的作用和因此导致环境的变化，以及由此引起的对社会和经济发展的影响。

A．经济活动

B．社会活动

C．人类活动

D．建设项目