Câu tường thuật - dạng câu kể 

S + said to / told + O + (that) + S + V (lùi thì)

S + said + (that) + S + V (lùi thì)

Câu tường thuật - dạng Wh-questions 

S + asked / wanted to know / wondered + (O) +WH + S+ V (lùi thì)

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33. If I became rich, I would travel around the world.

if 2: if + S + V2/ed, S + would / could + V1 

34. Most people had left before the volcano erupted. 

QKHT + before + QKD 

35. New devices have been invented to help people live a longer life by scientists.

S + has/have+ been  +V3/ed: bị động - HTHT

36. She said that she didn't know where her shoes were.

HTD --> QKD

37. The office manager wondered why he hadn't got a computer before.

QKD --> QKHT

38. Mai said that she came from a small village in Viet Nam.

HTD --> QKD 

39. She wanted to know what they were doing.

HTTD --> QKTD 

40. Daniel asked me where I was going on my vacation that month.

HTTD --> QKTD

this --> that 

`color{orange}{~MiaMB~}`