bạn tham khảo nhé 
1. Study hard or you will fail in the entrance exam

<=>If you don't study hard, you will fail in the entrance exam .

2. I can't go to Vung Tau beach this weekend

<=>I wish..i could go to Vung Tau beach this weekend.

3. Mother said, " Lan, you must finish your homework before 5 o'clock"

<=>Mother said that lan must finish her homework before 5 o'clock..

4. He said: " The earth revolves around the sun"

<=>He said that the earth revolves around the sun..