`1.` The teacher asked the students how many planets there were in the solar system.

`-` Câu tường thuật : S + asked + O + wh + S + V(lùi thì) + ...

`-` Biến đổi thì : HTD `->` QKD

`2.` The astronaut said to us that he was going to travel to space the following month.

`-` Câu tường thuật : S + said to + O + that + S + V(lùi thì) + ...

`-` Biến đổi thì : HTD `->` QKD

`-` Biến đổi thời gian : next month `->` the following month

`3.` Kate asked Andy if she wanted to buy a laptop at that shop.

`-` Câu tường thuật : S + asked + O + if + S + V(lùi thì)

`-` Biến đổi thì : HTD `->` QKD

`-` Biến đổi : this `->` that

1. The teacher asked the students how many planets there were in the solar system

- Câu gián tiếp: HTĐ -> QKĐ

- Wh-question: S + reported verb (asked (O)/ wondered/ wanted to know/...) + Wh.qu + S + V(lùi thì)

2. The astronaut told us he/she was going to travel to space the following month

- Vì người nói là "astronaut": chuyển I -> he/she (vì không rõ giới tính nên cái nào cũng được)

- am/is/are going to + V(inf) -> was/were going to V(inf) 

-  S số ít nên dùng was

- next  -> the following 

- Câu khẳng định/ phủ định: S + reported verb (said (to O)/ told s.one/... (that) + S + (not) + V(lùi thì)

3. Kate asked Andy if he wanted to buy a laptop at that shop

- Vì ngôi 2 (người được hỏi là Andy): chuyển you -> Andy/he

- HTĐ -> QKĐ: V_ed/2

- this -> that

- Yes/No question: S + reported verb (asked (O)/ wondered/ wanted to know/...) + if/whether + S + V(lùi thì)