Question

on the west of , in the west of 和 to the west of 三者的区别和用法 。

Answer 1

他们都是在西方，但是具体位置不同,比如：
on the west of China 指的是不属于中国但与中国接壤
in the west of China 指的是属于中国并位于中国的西方，如新疆
to the west of China 指的是不属于中国且不与中国接壤
例：Japan is to the east of China.

Answer 2

on the west of在…的西面
in the west of在…的西部
to the west of在…以西
Thailand is on the west of Laos

Here grass grows well, so, in the west of Britain, Most farms are animal farms

I will travel to the west of country this summer
大体上没什么区别，细微的区别只能靠语感来判断。