請問英文Part Of Speech!!!

She has great (belief) in her doctor.
In this sentence , (belief) means 信念,看法.
It means something (not people).
I am not a great (believer) in maths. exercise.
In this sentence. (believer) means 相信...者.
It means some people.
It is hardly (believable) that birds can talk.
In this sentence, (beliveable) is not a noun but an adjective.
It means 可信的.
Hope can help you.