1. I started home immediately after receiving the telegram.
2. After observing these rules you may avoid many mistakes.
3. On entering the room he greeted everybody.
4. After having sat there for a few minutes they continued their journey.
5. He made a few mistakes while copying the text.
6. I am thankful for having been stopped in time.
7. I remember having read this book.
8. After having tried all the keys on the ring she finally found the right one.
9. He is proud for having never been beaten at chess by his fellow students
10. ?
11. His arm was not in a sling and showed no sign of having been injured.
12. By reading more you can improve your knowledge of English.