how much are the blue trousers?I would like to buy that pair of jeans?how much is it?为什么上面用are,下面用is?
问题描述：
how much are the blue trousers?I would like to buy that pair of jeans?how much is it?
为什么上面用are,下面用is?
答
how much are the blue trousers? 这个句子中裤子是复数，只能用are
I would like to buy that pair of jeans? how much is it?这个句子中作者特指买那一条牛仔裤，是一条 that pair of ，pair是单数，一条裤子的话，自然用单数了
答
上句主语是 the blue trousers ,复数
第二句主语是 that pair of jeans ,看做整体,在于pair ,所以用 is.