Trang said to him that she could help him the next day.

→ Công thức chung của câu tường thuật: S + asked/ told sb + that + Mệnh đề lùi thì

Lùi động từ khuyết thiếu can sang could.

Tomorrow chuyển thành the next day/ the following day/ the day before

Note: said ⇒ said that

said to sb ⇒ told sb that

"I can help you tomorrow”, Trang said to him.

→ Trang said to him that she could help him the following day/ the next day.

⇒ câu tường thuật dạng trần thuật: S + said/ told +O/ said to +O + (that) + S + V(lùi thì)

* Một số thì của động từ lùi thì:

- HTĐ → QKĐ

- HTTD → QKTD

- HTHT → QKHT

- HTHTTD → QKHTTD

- QKĐ → QKHT 

- QKTD → QKHTTD

- is/am/are going to → was/were going to

- can/ will/ shall/ may/ must + V0 → could/ would/ should/ might/ had to + V0

* Cách biến đổi trạng từ chỉ thời gian và nơi chốn:

- today → that day

- tonight → that night

- tomorrow → the next day/the following day

- yesterday → the day before/ the previous day/ the period day

- ago → before

- now → then

- this → that

- these → those

- here → there