How are you?

Not so well.
Not so good.
Not so fine.
Not very good.
Not very well.
Not very fine.
Not too good.
Not too well.
Not too fine.

(Can we use all the expressions as the answer to 'How are you?' Would you correct errors?)

All sound okay, but the two with "fine" in them are not commonly used.

Yes, you can use all of these expressions as answers to the question "How are you?" However, some of these expressions may sound more natural or commonly used than others. Here are the corrections for the expressions you provided:

- Not very well.
- Not very good.
- Not very fine.
- Not too well.
- Not too good.
- Not too fine.

These are all acceptable ways to express that you are not feeling well or good. However, it is worth noting that if you are responding to a question in conversation, it might be more appropriate to provide a specific response or elaboration, such as "I'm feeling a bit under the weather" or "I'm a little tired today."

Yes, all the expressions you listed can be used as responses to the question "How are you?" They convey the idea that you are not feeling well or fine. However, it is more common to respond to this question by saying "Not so well" or "Not very good." The other expressions are also valid but may be less frequently used in everyday conversation. There are no errors in the expressions you provided.