1. Marry told him that she would phone him the following day.

Lùi về 1 thì : will -----> would, tomorrow ---> the following day. chuyển đổi tân ngữ

2. Lan said she had to go to the school libary then.

Hiện tại đơn---->Quá khứ đơn

Now ----> then

3. She said she would be there at two o'clock

Lùi về 1 thì : will -----> would, here ----> there

4. Her father asked her that he could wait for her about 15 minutes

Lùi về 1 thì : can ----->could

5. He said that there were no light in his room.

Lùi về 1 thì : hiện tại đơn-----> quá khứ đơn

Chuyển đại từ nhân xưng: my---> his