97. They said that they were driving to Chicago
99. She said that she had gone to the dentist the day before

97. They said (that) they were driving to Chicago.
98. He said (that) he didn't know what had happened
99. She said (that) she had gone to the dentist the day before.

Dạng chuyển câu trực tiếp - gián tiếp cần chú ý
- Đổi chủ ngữ, tính từ sở hữu (your, my, our,..)
- Đổi thì trong câu
- Đổi các trạng từ thời gian, địa điểm