In this lesson, we look at how to use the tricky prepositions for, since and ago. For is used for a period of time that something goes on. I’ve been working for hours. I’ll do the job for a year.

Like phlogiston, spontaneous generation and gnomes, the preposition rule started with an idea that felt right in another time but has ... never ended sentences with prepositions in casual speech ...

In this lesson, you will test your understanding of prepositions of place and direction ... It shows that the speaker had spent time swimming or surfing in 'the water'. 'On' is also a preposition.