英语简单句并成带定语从句的复合句 the plane was late.it was going to tibet

The plane which was going to tibet was late.
再问： 1....the necklace is worth more than five hundred dollars. polly stole it . 2....the man is in the nextroom . he brought us the letter yesterday.
再答： 1.Polly stole the necklace that is worth more than five hundred dollars. 2. The man who brought us the letter yesterday is in the nextroom.