Sử dụng đại từ quan hệ ( Who, Whom, Which, That ) để kết hợp các cặp câu, dùng dấu phẩy khi cần thiết.
1. This subject is very important. We are going to discuss it.
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2. Mr. Brown is coming today. He teaches me French.
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3. Tom loves his parents's house. He was born in that house.
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4. Do you remember the year? The Second World War ended in that year.
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