Much___to fight against pollution.A.have been done B,has been done C,had been done D.has done

问题描述:

Much___to fight against pollution.A.have been done B,has been done C,had been done D.has done
为什么是选B?

much是不可数名词,后面接单数形式,同时,全句意思是:为治理污染,(到现在为止),已经做了很多的事.所以用现在完成时态,且,事情是“被做”,所以要用被动语态.