56."I'm having a bath," she said
->She said that she was having a bath.(lùi thì HTTD->QKTD,I->she)
57. "I must do my homework tonight," he said to me.
->He said to me that he had to do his homework that night.(câu này không lùi thì,I->he,my->his,must->had to,tonight->that night)