通常用to的情况：
(1)destination 目的地
We are going to Paris.
我们要去巴黎。
(2)Distance 距离
It is about ten meters from my house to the university.
从我的家到大学也就十米。
(3)Giving 给
I gave the book to Mumu for reading.
我把书给木木读。

通常用for的情况：
(1)Benefits 影响（好处/坏处）
Yogurt is good for your stomach.
酸奶对你的胃好，
Too much sun light is bad for your skin.
晒太多太阳对你的皮肤不好。
(2)Period of time 时间段
I have been doing podcasts for 8 months now.
我已经录了八个月节目了。
(3)Scheduling 安排
I made an appointment for the 30th of March.
我在三月三十号又个约会。
(4)Doing something to help someone 帮助
Could you carry these books for Mumu？
你可以帮木木搬这些书吗？

我用这个枕头枕着睡觉。
I am using this pillow for sleeping.
I am using this pillow to sleep.