Question

请问：Mexico's neighbors are the U.S to the north.这里的to是介词吗?

Answer 1

to 是介词.

U.S. to the north ,其中 to the north是固定用法,”.的北面 “ ,比如： the key to the door,此处的 to也是 固定用法,翻译成 门的钥匙.