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1. Before he bought a cassette, he had checked the prices.
After he had checked the prices, he bought a cassette.
2. Before he felt a little better, he had taken some medicine.
After he had taken some medicine, he felt a little better.
3. Before they fought, they argued.
After they had argued, they fought.
4. Before she had a fatal accident, she had gone out for a walk.
After she had gone out for a walk, she had a fatal accident.