Combine two sentences into one using ''when''
1, Lunar Tet is the pappiest day. We often gather for meals on that day.
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2, She was busy last Sunday. I called her on that day.
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3, Mother's day is the day. Children show their love to their parents on that day.
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4. Do you remember the day? We first met each other on that day.
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5, I remember the day. We fought each other on that day.
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6, I can't forget the day. I first visited your house on that day.
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