@Huyền
1.The car has been broken down. This means we can't use it. ( Which)
-> The car has been broken down, which means we can not use it.
2. He failed the examination. This made his parents disappointed ( which)
-> He failed the examination, which made his parents disappointed.
3. She isn't at home. This means we can't meet her now ( which )
->She isn't at home, which means we can't meet her now.