There were five participants in the discussion. (took)

--> Five people (a)   the discussion.

Peter was ready to leave the office when his boss asked him to type up a report. (point)

--> Peter was (a)   the office when his boss asked him to type up a report.

Her precious novel was far more interesting than her new one. (nothing)

--> New new novel was (a)   as her previous one.

By chance I was there when she revealed the truth. (happened)

---> I (a)   when she revealed the truth.

Riding a bicycle along a pavement is against the law. (mustn't)

--> You (a)   along the pavement.

She has not gone out with him for almost two years. (stopped)

--> They (a)   two years ago.

In the end, I felt I had been right to leave the club. (regrets)

--> I (a)   about leaving the club in the end.

People believe that the explosion was caused by terrorists.

---> The explosion is believed (a)   by terrorists.

During the teacher's absence, the class was very noisy.

--> While (a)   , the class was very noisy.

He brought the umbrella along but it didn't rain.

---> He needn't (a)   along.

The builder is going to mend my roof tomorrow.

--> I am going to (a)   tomorrow.

They do not clean the windows so the room looks rather dark.

--> Were they (a)   , the room wouldn't look rather dark.

She dances beautifully and sings sweetly too.

--> Not only (a)   but she also sings sweetly too.

I FIND MEN'S WEARING DRESS IN SCOTLAND VERY STRANGE. (ACCUSTOMED)

--> I (a)   MEN'S WEARING DRESS IN SCOTLAND.

I couldn't finish my work without my friend's help.

---> If it (a)   , I couldn't finish my work.

You should book the table beforehand if you want to get a good seat in that restaurant. (advance)

--> The table (a)   if you want to get a good seat in that restaurant.

Dad helped me with my homework last night. (hand)

---> Dad (a)   with my homework last night.

It is useless to worry about what has already happened. (point)

--> There is (a)   what has already happened.

He speaks more persuasively than his brother.

--> He is (a)   than his brother