1. Lucky, luckily, unluckily
+ She was so lucky that she could win the lottery
+ Luckily, noone was dead in the accident.
+ Unluckily, she didn't pass her final exam
2. Peace, peaceful, peacefully.
+ Lisa is good at keeping the peace within her family

+ Da lat has a peaceful atmostwhere.
+ They are doing their homework peacefully.
3. Orphan, orphanage.
+ He is a orphan, and that's an important element makes him successful.
+ That orphanage is so beautiful and peaceful.
4. Humor, humorous, humorously, sense of humor:
+ My father has a good humour, and he starts to work very early.
+ That story is really humourous and interesting.

+ They are talking humorously

+ My friends' senses of humor always make me laugh.
5. Invent, inventor, invention.
+ Mark always invents machines to help his father work.
+ My uncle is an incredible inventor in my house.
+ Internet is truly a wonderful invention in the human's history.