a cool rain was falling,mixed with snow

题目

a cool rain was falling,mixed with snow
为什么用mixed 雨难道是被混合吗被谁混合啊
为什么不用mixing
2 if law-breaker went unpunnished, the society will be in disorder
为什么用went 不用made 或者came
3. in order not to be disturbed, i spent three hours locked in my study
为什么用locked 啊
他还有的选择是locking ,to lock, being locked
4if you go to xi'an, you will find palaces there more magnificent than commonly supposed
为什么用supposed这里的主语不是you 吗应该是主动啊

答案

1.雨被雪混合.这里的mixed with snow是定语从句,修饰rain,省略了that is,换个说法就明白了：A cool rain that/which is mixed with snow was falling.
2.首先这里用了虚拟语气,所以用go的过去式went.went在这里做系动词,表示持续发生的动作或状态,而came(come)和made(make)无此用法.