"We are going to the cinema," they said.
→ They said that they were going to the cinema.
"Do you know the answer?" asked the teacher.
→ The teacher asked if I knew the answer.
"Where are my keys?" my brother asked us.
→ My brother asked us where his keys were.
"I don't like spinach," said Mary.
→ Mary said that she didn’t like spinach.
She said, "I can't attend the meeting at 4 pm."
→ She said that she couldn’t attend the meeting at 4 pm.
My daughter said to me, "I want to be an environmentalist when I grow up."
→ My daughter told me that she wanted to be an environmentalist when she grew up.
Asked my friend, "Whose parrot is this?"
→ My friend asked whose parrot that was.
"Is the store open?" the customer asked.
→ The customer asked if the store was open.
"What time does the train leave?" he asked.
→ He asked what time the train left.
She said to me, "I'll visit my uncle next month."
→ She told me that she would visit her uncle next month.
The doctor told me, "You should come here tomorrow."
→ The doctor told me that I should come there the next day.
My friend asked, "Are you writing a complaint letter?"
→ My friend asked if I was writing a complaint letter.
The student said, "People must stop illegal hunting to protect wild animals."
→ The student said that people must stop illegal hunting to protect wild animals.
Sophie wondered, "Why does your family want to move to Japan?"
→ Sophie wondered why my family wanted to move to Japan.
The man said, "There may be an earthquake next Monday."
→ The man said that there might be an earthquake the next Monday.

Lưu ý về cách chuyển đổi câu tường thuật:
Trong câu hỏi gián tiếp (reported questions), ta thường dùng "if" hoặc "whether" cho câu hỏi yes/no (có hay không), và thay đổi từ "do" thành động từ thích hợp khi chuyển từ câu hỏi trực tiếp.
Các động từ và tenses trong câu trực tiếp thường thay đổi khi chuyển sang câu tường thuật.Ví dụ: "am/is/are" → "was/were", "will" → "would", "can" → "could"...