DEAR EXPERTS,

PLZZ ANSWER IT FASTTTT.....A MEETING WAS CONVENED ____THE HEADMASTER ___CONGRATULATE THE BOY___HIS BRILLIANT PERFORMANCE ___THE EXAMINATION.

THERE ARE A LOT OF PEOPLE __THE PLATFORM.

THE OLD COUPLE NEVER LEAVE THIER HOME_NIGHT _FEAR THAT ROBBERS MIGHT BREAK_.

 PLZZ ANSWER IT FASTTTT.....A MEETING WAS CONVENED _by___THE HEADMASTER _to__CONGRATULATE THE BOY_for__HIS BRILLIANT PERFORMANCE _in__THE EXAMINATION.

THERE ARE A LOT OF PEOPLE _on_THE PLATFORM.

THE OLD COUPLE NEVER LEAVE THIER HOME since that_NIGHT for_FEAR THAT ROBBERS MIGHT BREAK_.

hope it helps........8)

 Kruthi, you made some mistakes in the last sentence, otherwise your answer is correct.

A meeting was convinced by the headmaster to congratulate the boy for his brilliant performance in the examination.

There are a lot of people on the platform.

The old couple never leave their home at night of the fear that robbers might break in.

1st;by, on, in

2nd;in 

3rd;at ,for, in

my question is why?????

You will understand all this, if you learn the concepts of these prepositions.

For instance, in the second sentence, the people are on the platform, means that they are standing in the platform.If you say, the people are in the platform, that would mean that they are inside the platform!

Just like this, each of the sentences are framed.I will try to help you if you have any other doubt.

but my teacher said that it is in .

1 by

2 to

3 for 

4 in

5 on

6 at

7 in

i think it helps ..........: 3

I'm sorry to say,, but I think your teacher  might be wrong.Let others anwer too.Let's see then...