_______caused the accident is still a complete mystery.
It ____ we had stayed together for a couple of weeks_____ I found we had a lot in common.
---I think sometimes watching TV will cause visual pollution to the teenagers.---_________.
You had better ____ some money for your daughter.
When the children are busy playing their games.They had better be _____
The boy made ____ fun of me, so I became angry ____ him.