The first thing ___________ we should do is to clean the room.
You should do all ___________ I told you to do.
The book has nothing ________ interests me.
The naughty boy can do something _________ will give you trouble.
This is the tallest building ___________ I have ever seen.
You can take anything ___________ you like.
This is the best film ________ has been shown this year.
He took away everything __________ belonged to him.
There is no person ________ is always in the right.
This is the very person __________ I need.
參考答案:先行词是something时，关系代词用that或 which都 可以
先行词是someone,anyone ,everyone,somebody,anybody,noboday,everybody时关系代词用than 和who都可以，
先行词被all,every, very ,no,some ,any ,little,much等修饰时用that
先行词被序数词或形容词最高级修饰时，用that
先行词被the only,the very,the same,the last等修饰时用that
所以这几题都可以选that