新概念英语30课：课文上有句话是：the wayle is a small river that cuts across the park near my home
然后老师说了一个例句：he cut across the fields and got there in time.
来说明 cut across 是固定搭配,但是为什么例句中的cut across 不用加S呢.是因为是过去式吗,过去式都不用加S了?纠结Ing