merchandise是不可数名词

它是集体名词；表示一群人或物的名词叫集体(或集合)名词。形式上总是单数，没有复数形式，作主语时，谓语用单数。

The merchandise is reasonably priced and offers exceptionally good value.

这些商品定价合理，很是划算。

They could sell their merchandise for quadruple the asking price.

他们能够以4倍于要价的价钱出售他们的商品。

A really good catalogue can also whet customers' appetites for merchandise.

一份真正好的商品目录也可以激起顾客购买的欲望。