The key to exercise solutions in chapter Unit 116 - As for the textbook English Grammar in Use with authors Raymond Murphy from Cambridge University Press
Question
(Section B) Join sentences from the boxes. Begin each sentence with as.
Answer
As I was hungry, I decided to find somewhere to eat.
As today is a public holiday, many of the shops are shut.
As I didn't want to disturb anybody, I was very quiet.
As I don't know what to do, I need some advice.
As none of us had a watch, we didn't know what time it was.