How much do they cost对还是how much are the cost对How much do they cost对还是how much are they cost对
问题描述：
How much do they cost对还是how much are the cost对
How much do they cost对还是how much are they cost对
答
How much do they cost对
答
do ,,cost 是动词
答
How much do they cost 对
因为原句里有一个动词了,要用助动词do
答
do
be动词后不能接动词原形