3.If I were you, I would understand your problems.

1.If it rains, we will stay at home.

2.If you work so much, you will be tired.

3.If I were you, I would have understood your problems.

4.Unless he goes by car, he will be late.

5.Unless they have money, they will not buy it.

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tứ giác abcd có ab=cb=cd và góc a + góc b = 140 gọi o là giao điểm hai đường chéo tính góc aod