Question

that在句中是什么成分？

The Flatiron School, where people pay to learn programming, started as one of the many coding bootcamps that’s become popular for adults looking for a career change.

Answer 1

一、定语从句对前面的名词具有修饰、限制或描述功能；同位语从句对前面的名词具有补充、解释、说明功能.如：
The fact that she told us is believable.她对我们说的话是可信的.(that引导定语从句)
The fact that he once joined the army is believable.他曾当过兵这一事实是可信的.(that引导同位语从句)
二、that在引导定语从句时,不光要起连接作用,还要在从句中作成分,若that在从句中作宾语,则that可以省略；而that引导同位语从句时,只起连接作用,不充当从句中的任何成分,且一般不能省略.如：
Don’t you forget the promise (that) you made?难道你忘了你许下的诺言吗?(that在定语从句中作宾语,可省略
)He makes a promise that he will make you very rich if you work with him.他许下诺言：如果你和他一起干,他会使你很富有.(that在同位语从句中不作任何成分,且不省略)
三、定语从句前面的名词既可以是具体名词,也可以是抽象名词；而同位语从句所修饰词一般是少数抽象名词,从句说明该名词所指的具体内容,如：advice,answer,belief,doubt,fact,hope,idea,information,message,news,order,promise,proposal,possibility,story,suggestion,thought,truth,view,word等.
The patient accepted the advice that the doctor gave him.病人接受了医生给他的建议.(定语从句限定advice)
The patient accepted the advice that smoking should be given up.病人接受戒烟这一忠告.(同位语从句所表述的是advice的具体内容)
This is the book that I bought yesterday.这是我昨天买的那本书.(先行词为具体名词)

Answer 2

that在引导定语从句时是关系代词在从句中起代词作用代替先行词可以在定从中充当主语宾语等句子成分，充当宾语时that可以省略。在限制性定语从句中that有时也可以充当关系副词作定从中作状语，这种用法的that也可以省略。
that在引导名词性从句时是连接词仅起连接作用不能在从句中充当句子成分本身也没有意思，that在引导宾语从句时可以省略。

Answer 3

that在句中是个代词，代指最开始的The Flatiron School，在句中是做主语。

Answer 4

关系代词that在定语从句中做主语，that指one of the many coding bootcamps.

Answer 5

定语从句
关系代词that在从句中用作主语，指物
that指代one of the many coding bootcamps
可以私聊我

追问

请问在that’s become popular for adults looking for a career change里面，系动词是is还是is become呢？

追答

has
Be动词怎么可能跟动词呢？