语法上两个都对
go to 走去,走到
go into 走进（走进山里）
也有 go in the mountains 的说法
但我觉得人对两者的区别一般人不那么拘泥.
比如,下面第一句和第二句没有实质上的区别.
例：
People go to the moutains to escape the noise of the city
Leave the house and go into the mountains!There you will experience nature's quiet and cool charm.
On weekends we often go hiking in the mountains
我是加拿大人,前英语老师,