1- The lady may sell the house.
The house may be solved by the lady
2- Someone wrote the letter very badly.
The letter was written very badly by someone
3- Sameer is taking the books.
The books are being taken by Sameer
4- The police had caught the thieves.
The thieves had been caught by the police
5- The boys will have taken the exam by ten o'clock
The exam will have been taken by ten o'clock
6- He spoke the words quietly
The words were spoken quietly
7- People say this forest is more than a hundred years old.
I don't know .... maybe there is no passive for this sentence
8- Who saw her in the market yesterday?
Who was seen by them in the market yesterday? >>>>> ( I think it is wrong)
9- She invented us to dinner in the gallery this morning.
Here I think there are two answers because we have two objects( direct and indirect)
We were invited to dinner in the gallery this morning by her
The dinner was invited to in the gallery this morning by her
10- Has anyone taught you English before you came here?
Have you been taught English before you came here?Raghad
thanks for this nice topic.... Waiting you