F.  Rewrite the sentences with no sooner …..than

1. He got down to writing the letter as soon as he returned from his walk.

No sooner……………………………………………………..……………..

2. He had hardly left the office when the telephone rang.

 No sooner ……………………………………………………………………

3. I had only just put the phone down when the boss rang back.
No sooner ……………………………………………………………………

4. As soon as I got into the bath, someone knocked at the door.
No sooner ……………………………………………………………………