前面加介词on，例如：

1、She decided on reflection to accept his offer after all.经过审慎的思考，她决定还是接受他的提议。

2、On sober reflection， I don't think I really need a car after all.冷静地想了想以后，我觉得我其实并不需要车。

3、On Reflection: The Basis of Sustainable Development of Teachers.反思：教师职业生涯可持续发展的基础。

reflecti…

前面加介词for，例如：

1、The fashion at the time was for teaching mainly the written language.那时教学时兴的主要是书面语。

2、He's not cut out for teaching.他不适于做教学工作。

3、The number of applicants for teaching posts has tapered off.申请做教学工作的人数越来越少。

Two days前面加什么介词，看应该在什么场合下想表达什么意思。 For two days表示在一段时间之内。 In two days是两天之后，用于将来时。 For example， I will stay here for two days. He stayed in bei Jing for two days last year. He will be back in two days. We will go to Beijing in two days.