填to
一般名词后要跟定语需要用of连接,表示。。。的。。。。
如:experience of suiside
但是有些名词必须用to连接,包括:
1) key, answer, guide, clue, solution, approach, alternative, access, way, extrance, entry, exit
2) danger, hazard, threat, barrier, obstacle, challenge
3) objection, oppostion, exception
。