`11`. Tom asked Mary if she phoned him the night before.

- Đổi ngôi : you `->` she

- Tân ngữ : me `->` him

- Lùi thì : Quá khứ đơn `->` Quá khứ hoàn thành $(+)$ S + had + Vpp

- last night `->` the night before/ the previous night

`12`. I asked the policeman if he knew for far it was to the station.

- Đổi ngôi : you `->` he

- Lùi thì : Hiện tại đơn `->` Quá khứ đơn

`13`. Mary asked me if I could tell why I was so sad.

- Đổi ngôi : you `->` I

- Lùi thì : can `->` could ; Hiện tại đơn `->` Quá khứ đơn

`14`. She asked me if John was my good friend.

- Lùi thì : Hiện tại đơn `->` Quá khứ đơn

- Tính từ sở hữu : your `->` my

`15`. She asked us if we were hungry.

- Đổi ngôi : you `->` we

- Lùi thì : Hiện tại đơn `->` Quá khứ đơn 

* Câu tường thuật với Yes/No-questions : S + asked/ wanted to know/ wondered/... + (O) + if/whether + S + V (lùi thì)

`-` Tường thuật NV ( Yes / No ) :

`=>` S + asked + O + if / whether + S + V ( lùi thì )

`*` HTĐ `->` QKĐ : S + Ved / V2 `-` S + was / were + adj / n

`*` QKĐ `->` QKHT : S + had + VpII

`*` Can `->` Could

`11`.Tom asked Mary if she had phoned him the previous night

`12`.I asked to the policeman whether he knew how far it was to the station

`13`.Mary asked me whether I could tell why I was so sad

`14`.She asked me if John was my good friend

`15`.She asked us if we were hungry

`\text{# TF}`