1. He is the boy who saved the drowned kid a couple of days ago.(主语)
2. He is the boy whom a young man saved a couple of days ago.(宾语)
3. He is the boy whose father saved a kid a couple of days ago.(定语)
4. He saved a kid two days ago when it was freezing cold.(时间状语)
This is the book which I hope to get.(which 作从句的宾语)
这本书正是我想要的。
You should put a cup of hot water on the cupboard where the kid can
not reach.(where 作地点状语)
你应该把热茶放在柜橱上,放在那里孩子够不着。