1. If we had taken the train, we wouldn't have been late for the meeting.
-> If 3: If + S1 + had + Vpp, S2 + would have + Vpp
2. The meat was so rotten that I had to be thrown away.
-> S + be + so + adj + that + S + V
3. You don't have to finish by Saturday.
-> neccessary = have to = need
4. The youth was made to empty his pocket by the police.
-> Bị động với "make" S + be + made + to V
5. It takes six-hour to drive from London to Edinburgh.
-> It + takes + SO + thời gian + to V
