9.Mark said that his friend had found a new jon in the music business (my -> his , QKĐ -> QKHT)

10.Judy complained that she had already written that essay four times (HTHT -> QKHT , this -> that) 

11.Peter annnounced that he would not give up until that factory was shut down (will -> would , this -> that , is -> was)

12.Her boyfriend told her that she had bought a wonderful dress (you -> she , HTHT -> QKHT)

* Cấu trúc câu tường thuật : 

S + say/said/tell/told + (sb) + (that) + S + V(lùi thì) + ... 

* Lùi thì : 

HTĐ -> QKĐ

HTTD -> QKTD

QKĐ -> QKHT

HTHT -> QKHT

QKHT -> QKHT

HTHTTD -> QKHTTD

QKTD -> QKHTTD

can -> could 

may -> might 

will -> would 

* Các modal verb không lùi : might , could , ought to , should