Indirect questions + preposition (3)

Have a look at this conversation. 

A: Excuse me. What is the professor talking about? 

B: Sure. He is talking about the crisis during the pandemic. 

A: Thank you. And who do these books belong to? 

B: Yes, they are mine. 

A: Oh, I see. 

Question pattern 1

In questions beginning from Who…? / What…? / Where…? / Which…?, prepositions (to/from/about/by, etc) usually go at the end.  

QUESTIONS with “AT” at the end

What are you looking at? 

Who was she looking at? 

What are they laughing at? 

QUESTIONS with “TO” at the end

Who was she talking to? 

Which school did you go to? 

Who did you send these pictures to? 

QUESTIONS with “ABOUT” at the end

What are you talking about? 

What was the meeting about? 

What are you worried about 

QUESTIONS with “FROM” at the end

Where did this come from? 

Who did you get that present from? 

Who did you get this from?

QUESTIONS with “FOR” at the end

What are you waiting for? 

Which candidate are they going to vote for?

What food is that city famous for?

QUESTIONS with “WITH at the end

Who did you watch a movie with? 

Which card did you pay with? 

Who did you play tennis with?