11.   When I knocked at the new door and got no response, I opened it and saw Minna sitting on the sofa.

12.   Years later, Ogwen apprenticeship having been served, we began to aspire to their routes, knees knocking at our effrontery.

13.   One morning I was sitting at my desk when a policeman knocked at my door.

14.   Knock at the rear entrance.

15.   I knocked at the front door and there was no answer.

16.   I knocked at the front door, but there was no answer.

17.   Johnnie knocked at her door.

18.   Yesterday a beggar knocked at my door.

19.   He asked me for a meal and a glass of beer.

20.   She was about to retire when Sarah knocked at her door.