1. The man standing there is a clown.
2. The envelop lying  on the table has no stamp on it.
3. Benzene, discovered by Faraday, became the starting point in the manufacture of many dyes, perfumes and explosives. 
4. My grandmother, being old and sick, nerver goes out of the house.
5. The student don't know how to do exercise given by the teacher yesterday.
6. The diagrams made by young Faraday were sent to Sir Humphry Davy at the end of 1812. 
7. The gentle living next door to me is a well-known orator. 
8. All the astronauts orbiting the earth in space capsules are weightless.
9. All student not handing in their papers will fail in the exam.
10. I saw many houses destroyed by the storm.
11. The street leading to the school is very wide.
12. The system used here is very successful.
13. Mr.John, teaching my son, is my neighbor.
14. Trains leaving form this station take an hour to get to London.
15. The candidates sitting for the exm are all from Vietnam.
16. We are driving on the road built in 1980.
17. Customers complaining about the service should see the manager.
18. The city destroyed during the war has now been rebuilt. 
19. My brother, meeting you yesterday, works for a big firm.
20. The vegetable sold in the shop are grown without chemicals.