1.We couldn't have managed without my fathe's money.
=>.If .we had not had my father's money, we wouldnot have managed
2.I had only just put the phone down when the boss rang bạck
=> Hardly.had I put the phone down when the boss rang back
3. We may not be able to give the concert.
=> The concert may have to be cancelled. 
4, I only recognized him when he came into the light.
= > Not until he came into the light did i recognize him 
5, It is quite pointless to complain
⇒ There is no point in complaining
6, As far as I know he is still working in Bristol 
To the best of my knowledge, he is still working in Bristol
7, It was his incompetence which led to their capture.
⇒ If it hadn't been for his incompetence, they wouldn't have been captured
9, .In the end,I felt I had been right to leave the club
=>  I had no regrets about having left the club. 
10, .He talked about nothing except the weather (sole)
=>  His sole topic of conversation was the weather.

​3) We may not be able to give the concert 
=> the concert may have to be cancelled.
4) I only recognized him when he came into the light.
=> Not until he came into the light di I recognize him.
5) It is quite pointless to complain.
=> There's no point in complaining.

6) As far as I know he is still working in Bristol 
=> To the best of my knowledge, he is still working in Bristol
7) It was his incompetence which led to their capture.
=> If it hadn't been for his incompetence, they wouldn't have been captured
9) In the end,I felt I had been right to leave the club
=>  I had no regrets about having left the club. 
10) He talked about nothing except the weather in this first date
=> His sole topic of conversation was the weather in this first date.