Plastic bags have caused serious environmental pollrtion,____ A haven't they B have theyC don't they D do they

问题描述:

Plastic bags have caused serious environmental pollrtion,____ A haven't they B have they
C don't they
D do they

选择A
这里考察的是反义疑问句
因为前面是have caused这个完成时,而且是肯定,所以后面部分应该是否定的,而且是havn't they,选择A