⑤ Helping others is a habit which you can learn ev

问题补充：

⑤ Helping others is a habit,which you can learn even at an early age.

答案：

absolutely correct.

其实 that/ one / so/.都可以代替which,没绝对的对错,what 不可以

======以下答案可供参考======

供参考答案1:

语法上没有错误