preposition
It was through his good graces that I got the appointment
The dog barked all through the night
When I say 'the third through the sixth' I mean 'including the sixth'
I went through a lot of trouble to find this book
adjective
Let me know when you are through. How many times has she sworn she was through with him forever?
adverb
I am just passing through
By the time I got home, I was soaked through