My sister hates me laughing at her.

--> My sister (a)  

They gave the boys some money.

--> Some money (a)  

She makes the boy study the lessons.

--> The boy (a)  

What subjects do we study on Mondays?

--> What (a)   ?

People say that Tom was sick a day ago.

--> Tom (a)  

People know that he lives near here.

--> He (a)  

It is said that Mary can sing very well.

--> Mary (a)  

The boys have Peter clean the floor.

---> The boys have (a)  

Don't let Tom annoy you.

--> Don't let (a)