It's not an idiom. It's American slang for money, because American paper bills are green (and they fold when you put them in your pocket).
Folding Green
It's not really an idiom. It means "what are you thinking about."
"to be green" is to be new at something, inexperienced, a rookie or novice
Green and folding generally refers to money, in particular bank notes.
It means swearing violently and creatively.
It means the person looks sick. Usually they are pale and green in the face.
she really got the attention
It means that you really know it.
The idiom, "Take his temperature" is an idiom because his temperature is not really being taken away from him, it is actually being measured. In fact, the temperature of his body is being measured - that is your answer.
it means when you are really nervous and cool at the same time.:)
Meaning you are pretending to be bigger or smarter than you really are
This is not an idiom that I have ever heard. Perhaps you mean an arm AND a leg, which is an exaggerated way of saying something is really expensive.