Combine these pairs of sentences, using a relative pronoun. Put comma(s) where necessary.
1/ Is that the room? You intended to put the piano in it
->
2/ Mrs.Lan was very gentle. I picked up her umbrella accidentally
->
3/ We have not decide the day. We'll go to London then.
->
4/ These tubes need soldering at once. They have leaks
-> 
5/ My youngest sister has just got married. You met her at my home last week.
->