20．  Consumers may not think of household cleaning products to be hazardous substances，but many of them can be harmful to health，especially if they are used improperly．

(A)  Consumers may not think of household cleaning products to be

(B)  Consumers may not think of household cleaning products being

(C)  A consumer may not think of their household cleaning products being

(D)  A consumer may not think of household cleaning products as

(E)  Household cleaning products may not be thought of, by consumers，as

答案是D。

但是为什么不是E呢？我觉得but many of them中的them应该指代前面句子的主语，所以前面的主语应该是Household cleaning products啊。

请大家帮忙解疑。

恩,楼主的看法是对的,但是D是主动语态,优于Ｅ中的被动语态,D中a consumer 是单数,所以后面的them只能只带主句中的products

那是不是说them的指代并没有固定规定应该指向前面哪个名词，如果D选项改为Consumers may not think of household  cleaning products as的话，反而存在指代不清的问题？也就是说其实E也存在指代不清的问题？