1. Because
2. so
3. as
4. Because of
5. Since
Ex 2:
1. Paul was an hour late becaus he missed the train.
2. I borrowed your lawn mower as you weren’t using it.
3. We had no electricity during the storm so we had to use candles.
4. He studied hard for the test since he needed a good mark.
5. We have decided to stay at home as it's raining.
6. Tom won’t be able to go with us to the theatre because he has to work.
7. The windows were all open. Consequently, a lot of mosquitoes came into the room.
8. We knew what to expect. Therefore, we were not surprised at what happened.
9. He asked nicely since you would consider it.
10. Mary joined the school theatre as she wanted to increase her circle of friends.
11. I’ll take a taxi as I don’t know the way.
12. I can’t read my email as I´ve forgotten my password.
13. I got home late because of a flight delay.
Ex 3:
1. Sue didn’t put on her sweater after the race so she got a cold.
2. I turned the heating on since it was very cold.
3. The lamp didn’t work so I took it back to the shop.
4. Dave doesn’t drive because he always travels by train.
5. Would you mind picking up some trash bags as you are going by the store on the way home from work?