1. Because paper of all kinds is the biggest single component of municipal trash, many municipalities have tried recycling to reduce the cost of trash disposal.
(A) Because paper of all kinds is the biggest single component of municipal trash, many municipalities have tried recycling to reduce the cost of trash disposal.
(B) Because paper of all kinds is the biggest single component in municipal trash, many municipalities tried to recycle so that the cost of trash disposal is reduced.
(C) Because paper of all kinds are the biggest single components in municipal trash, many municipalities have tried to recycle to reduce the cost of trash disposal.
(D) All kinds of paper are the biggest single components of municipal trash, and so many municipalities have tried recycling to reduce the cost of trash disposal.（A）
(E) All kinds of paper is the biggest single component of municipal trash, so many municipalities have tried to recycle so that the cost of trash disposal could be reduced.
这道题的答案是A，可是我不清楚try to do,try doing 该怎么分别，另外就是B除了这个之外还有什么错误呢？
谢谢。 | 
