"anyone" 后面使用 "who" 还是 "that" 取决于你所描述的人是指人还是事物。一般来说，"who" 用来引导描述人的定语从句，而 "that" 则可以用来引导人或事物的定语从句，但在口语中有时也会用 "who" 来指代事物。
举例来说：
1、当描述一个人时，应该使用 "who":
She is someone who knows a lot about computers.
Is there anyone who can help us with the project?
2、当描述人或事物时都可以使用 "that"，尽管有些人认为 "who" 更礼貌或更符合正式写作的规范：
I need a book that explains the basics of physics.
Do you know anyone that can fix a leaking faucet?
虽然这两者在很多情况下可以互换使用，但在写作中，为了避免模糊不清，最好根据所描述的是人还是事物来选择使用 "who" 或 "that"。
"anyone" 是一个形容词，用于指代任何一个人。它是 "anybody" 的不定代词形式，表示不特定的人。
1、主语："anyone" 可以作为句子的主语，表示任何人。在这种情况下，动词通常使用第三人称单数形式。
Anyone can participate in the event.
Is anyone available to help me with this task?
2、宾语："anyone" 可以作为及物动词的直接宾语或介词的宾语，表示不特定的人。
I haven't seen anyone at the party.
She doesn't trust anyone with her secrets.
3、疑问句："anyone" 可以用于疑问句中，表示问是否有人能够做某事。
Has anyone called for me?
Does anyone know the answer to this question?
4、否定句：当与否定词连用时，"anyone" 表示没有任何人。
I haven't seen anyone in the park.
There isn't anyone who can solve this problem.