| I don’t understand the lesson because | | |
| John mailed the letter, but | | |
| The food spoiled because | | |
| You were cold because | | |
| They missed the speech because | | |
| Ken was tired this morning because | | |
| The students failed the test because | | |
| I took the bus to work because | | |
| The plants died because | | |
| You ran very fast, but | | |