for to 問題

作為 preposition, Yahoo 字典上, “for” 有36種用法, “to” 有20種用法
除此之外, verb + preposition 有時變了做 phrasal verb, 另外意義

We look to our parents for guidance.
We look for work. (look for = 尋找 )

I speak to him.
I speak for him.

I sell the car to him.
I sell the car for him.

You apply to a company
You apply for a job

I apologize to you.
I apologize for my absence.

Thanks to someone
Thanks for something

“for” 和 ”to”, meaning 完全地不同
基本上解釋
for (prep.) = 因為, 至于, 替, 代表, 擁護
to (prep.) = 到,向,往, 比, 對, 趨于,給
to 還用來 form infinitive ,不是 preposition
e.g. I want to go.

使用什麼 preposition, 要看 meaning, 是否 phrasal verb
看字的配搭 (Collocations), 是否 common expression

太多, 舉少少例子
wait for, vote for, beg for, strive for, for the time being, reserve something for someone,
for the sake of, for good, for life, respect for, for sale, for rent, thanks for

to 是 preposition:
object to, look forward to doing something, dedicated to, devoted to, resort to
in preference to something, indifferent to, pay attention to, adhere to, attach to, related to, committed to, adjacent to, move to tears

我贊成意見者:Dustin提議, “查字典！”

還有其他方法可以容易分辯嗎??
查字典！
查 'for' and then 查 'to'

http://wenku.baidu.com/link?url=K3f3RsRY3B4fkUNm5rV6m1aWvqnEzhlbtKCnExkVlIO-xV84MpJZ2frvH1KPECZ_cpNA-OhgYMKEPYlGR_mdvQEFvD_-Gq8h2ayxrD7pk1a