Are (be verb) +ing means the action is still going on. Means, it is present continuous tense or something is not yet done or finished. *I really appreciate your help. You are nervous. (You've concluded him being nervous. So, the action is done.) Are you crazy? Are-be verb You-pronuon Crazy-noun This is a simple question. Thus, no need to have the "ing" form of the verb.

I think this question requires a lesson to explain, it's a good question. Let me know if you need more help.

When you use (are) with (-ing) you are using the present continuous tense and it means that the action you are describing is happening now and will continue in the future. When you use (are) without (-ing) you are using the simple present tense and it is used in different ways.

Hi The word “are” is used as a linking verb in that instance! A linking verb will always connect the subject to a word modifying the subject (an adjective). That’s why the word “nervous” is an adjective that’s being linked by “are” to the subject “you.” Typically we only use “-ing” when we are using action words such as: The boys are playing. My dogs are eating. Your sisters are chatting. If you found this helpful then feel free to message me so we can learn more and improve your English together :)

In the first example, you would not use “are”. It sounds more natural to say: I really appreciate you helping. With the other examples, you are correct to not use -ing. 👍🏼