Because
She was late to the meeting. Traffic was heavy
She was late to the meeting *because* traffic was heavy
There is a lot to do. I took a break
*Although* there is a lot to do, I took a break
The baby was crying. She was hungry
The baby was crying *because* she was hungry
I love the house. I wish it were closer to my school.
*Although* I love the house, I wish it were closer to my school
He was tired. He stayed up too late studying for an exam
He was tired *because* he stayed up too late studying for an exam
We sang three more songs. Our voices were already tired from singing so much
*Although* we sang three more songs, our voices were already tired from singing so much
They missed their flight. They were late to the airport
The family missed their flight *because* they were late to the airport
The sun was shining brightly. It was very cold outside
*Although* the sun was shining brightly, it was very cold outside.
Team Alliance celebrated. They won their championship
Team Alliance celebrated *because* they won their championship
She loved reading books. She did not have a lot of free time.
*Although* She loved reading books she did not have a lot of free time.