What are you doing is the correct 'saying' or pronounciation. What you doing' is slang and is slightly shortened to make life easier, and of course we understand it.
No, The correct grammar for this sentence would be, "He finished doing his homework."
DBA or d/b/a
The correct answer is, they are doing their homework now, or they will do their homework now. The word do can be used as an action verb or an auxiliary verb.
The grammar appears correct even though it is heard more like, "He is capable of doing this job."
You need to give the context if you want a sensible answer. To do is the infinitive.
Were doing this is correct.
The correct sentence is the following: "What were you doing from before?"
The phrase "How is she doing?" is grammatically correct. It is a common way to inquire about someone's well-being or current status.
Neither. You are doing it...or...You're doing it.
Yes, the phrase 'what they're doing' is grammatically correct. For example: What they're doing is wrong.
No, The correct grammar for this sentence would be, "He finished doing his homework."
No, "hows you" is not grammatically correct. "How are you?" is correct.
It seems correct.
The sentence 'A school housed in the church is doing well,' is grammatically correct.
yes
No. It should say "How is Fred Martin doing?"
It is correct to say "Hope you and your family are doing well." This sentence allows you to convey your well wishes for both the person you are addressing and their family.