1. The man who is standing there is a clown.
--> The man standing there is a clown.
2.The envelop which is lies on the table has no stamp on.
--> The envelop lying on the table has no stamp on it.
3.Benzen, which was discovered by Farady, became the starting point in the manufacture of many dyes, perfumes and explosives.
--> Benzene, discovered by Faraday, became the starting point in the manufacture of many dyes, perfumes and explosives.
4.My grandmother, who is old and sick, never goes out of the house.
--> My grandmother, old and sick, never goes out of the house.
5.The students don't know how to do the exercises which were given by the teacher yesterday.
--> The student don’t know how to do exercise given by the teacher yesterday.
6.The gentleman who lives next door to me is a well-known musician.
--> The gentleman living next door to me is a well-known orator
7.I saw many houses that were destroyed by the storm.
--> I saw many houses destroyed by the storm.
8.The street which leads to the school is very wide.
--> The street leading to the school is very wide.
9.The system which is used here is very successful.
--> The system used here is very successful.
10.Mr Jackson, who teaches my son, is my neighbour.
--> Mr. Jackson, teaching my son, is my neighbour.