Question

It was essential that we sign the lease before

It was essential that we sign the lease beforethe end of the month.为什么不是signned呢？before可以换成at吗？

Answer 1

您好！这句话的中文意思就是： 我们必须在月底之前签署租约。

求采纳，谢谢亲！

Answer 2

这是虚拟语气的用法。
在It is +形容词(important, necessary, good, essential,right, wrong, better, natural, proper, funny, strange, surprising) +that从句中，谓语动词的虚拟语气用“(should)+动词原形”的结构。如橡漏岁梁睁：
It is natural that she (should) do so. 很自然她应该这样做。
before换成end语法上是对的，但含义有所变化。
before the end of the month在这搜友月底前
at the end of the month在这月底