a ticket to the concert,a key to my room为什么后面用to?类似的短语还有哪些？

确实,这种题没什么为什么,做的多了自然就会了
the answer to this question
the entrance to the building
还有些动宾结构的
如 a pen to write with
a piece of paper to write on
a question to answer
有些单词后跟of
如 your way of speaking
the best way of solving the problem
但应该说: the best method to solve the problem

固定搭配

1，仔细品，TO有一个方向的感觉。

2，我也同意楼上，即使有人都列出给你，也未必帮你记住。慢慢学，想一想，会记住的。

固定搭配。类似的短语还有：answer /entrance/reply/way...+to

an entrance to the hall
a highway to the city
the way to heaven
a promise to keep

用to是表示附属关系，而of是表示所属关系的。