As I know:
1. engineering圈找工必須有certificate嗎？
Not necessary, unless you work in a consulting company. Professional engineer (PE) is needed for some consulting companies.
2.engineer intern certificate 和 fundamental engineer certificate ， 前者是後者的基礎嗎？
FE is an exam, for engineering students and who want to be a Professional engineer (PE). FE is useless if you do not want to be a PE
did not know"engineer intern certificate"
Take FE exam first, then take the your major PE exam.
3. 如果有了FE， 是不是engineer intern工作就不能申請了，因為是低一級level的。
engineer intern is a position/title for students working in a company. you would not qualify for the position if you have graduated ().
