15: There were a lot of people at her birthday party. She had met only a few of these people before.

=> There were a lot of people she had never met before at her birthday party.

16: The mountain is the highest mountain in the world. It is called Everest. The mountain, Everest, is the highest mountain in the world.

17: Michiko has gone through several earthquakes. He has lived in Japan for 10 years.

=> Michiko, who has lived in Japan for 10 years, has gone through several earthquakes.

18: Here is the assignment. You must finish it before going to the class.

=> Here is the assignment that you must finish before going to class.

19: She has come up with some amazing ideas. We can discuss them at the meeting.

=> She has come up with some amazing ideas that we can discuss at the meeting.

20: The university guarantees accommodation in halls of residence. The freshmen can live there.

=> The university guarantees accommodation in halls of residence where the freshmen can live.

21: A boy was injured in the accident. He is now in the hospital.

=> The boy who was injured in the accident is now in the hospital.

22: There were some good programmes on the radio. None of the programmes I listened to.

=> There were some good programmes on the radio, but I didn't listen to any of them.

23: The package reached me this morning. My father sent it yesterday.

=> The package that my father sent yesterday reached me this morning.

24: Our school has a good laboratory. The students practice chemistry in this laboratory.

=> Our school has a good laboratory where the students practice chemistry.

25: My sister is thinking of opening an eating-house. She is an excellent cook.

=> My sister, who is an excellent cook, is thinking of opening an eating-house.

26: One reason was that the interview times were too short. The panel could not decide who was the best person for the job for that reason.

=> One reason the panel could not decide who was the best person for the job was that the interview times were too short.

27: The parcel arrived in the post at 11 am. I was still at work then.

=> The parcel arrived in the post at 11 am while I was still at work.

28: Students should get involved in environmental groups on campus. They are concerned with the environment.

=> Students who are concerned with the environment should get involved in environmental groups on campus.