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Join the sentences using Past Simple and Past Perfect.
1) I read the letter. I threw it away. (when)
2) He past his driving test. He bought a car. (as soon as)
3) I took the book back to the library. I finished reading it. (when)
4) I spent all my money. I went home. (when)

When I had read the letter, I threw it away.

As soon as he had passed his driving test, he bought a car.

I took the book back to the library when I had finished reading it.

When I had spent all my money, I went home.