1. The bed had no mattress so I couldnt sleep.

2. Romeo and Juliet were lovers whose parents hated each other.

3. That woman, whom are waiting for, is a secretary.

4. The man whom I had come to see was sitting at the desk.

5. This morning I missed the train which I usually catch.

6. He just gone to Mr. Lam's house where there is a party today.

`22`.The bed had no mattress. I slept on that bed. 

=> The bed on which I slept, had no mattress.

`23`.Romeo and Juliet were lovers. Their parents hated each other.

=> Romeo and Juliet whose parents hated each other, were lovers.

`24`.The woman is a secretary. We are waiting for her.

=> The woman whom we are waiting for, is a secretary.

`25`.The man was sitting at the desk. I had to come to see this man.

=> The man whom I had to come to see, was sitting at the desk.

`26`.I missed the train. I usually catch this train.

=> I missed the train which I usually catch.

`27`.He has just gone to Mr. Lam's house. There is a party there today.

=> He has just gone to Mr. Lam's house where is a party today.