in a proper way, waste can be turned into useful things.
A. To deal with
B. Dealt with
C. Dealing with
D. Being dealt with
网友回答
A. To deal with
(答案→)B. Dealt with
C. Dealing with
D. Being dealt with
解析：考察非谓语动词。句意：用恰当的方法处理，废物也能变成有用的东西。过去分析表示被动的发生过的动作，和句子主语是动宾关系。Dealt with的动作对象是waste，故选B。