The differences between "thought" and "idea"

[sula54]

Dear all,

Please help me with this question.

It is a good _______ to keep a second first aid kit in your car.
(A) thought
(B) feeling
(C) theory
(D) idea

I get the right answer. However, I don't know why "good idea" is better than "good thought" in this case since the dictionary says, "thoughts is a person's ideas and opinions about something."

I wonder if someone can explain to me what is the differences between "a good thought" and "a good idea". Thanks!

[cecilie]

Hi, I would say that "thought" is used when it "comes and goes", you may apply thought into practise, than it becomes idea!