The building is across from the school gate. 该建筑是在校门口对面。 一个好的完整的句子, is不用省略.追问
across from是一个动词，为什么需要用is？
追答
across from 不是动词; across 是动词; across from 是一个词组, ( across 动词 + from 介词 ) 如果不使用 across from, 它可以用 on the other side - The building is on the other side of the school gate. is 是动词, 在这两句中是不能省略.