请找出下列各句中的错误并加以改正。
1. The reason which he didn't go to school is that he was ill.
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2. Those who wants to go with me put up your hands.
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3. The boy, his mother died last year, studies very hard.
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4. I have two sisters, both of them are doctors.
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5. We're going to visit the school where your brother works there.
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6. He is the only one of the students who have been invited to the English Evening.
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7. That is the way which they work.
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8. Those have questions can ask the teachers for advice.
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9. Who is the man who has white hairs?
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10. I will never forget the days which we had a good time together at the sea.
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