[trans]

I look for advice on asking a question about the colour of object. Something confuses me here...
0. My father bought a green coat
How to ask a simple question, meaning "What colour was the coat he bought?"
1. What colour coat did he buy? (as if he bought some "colour coat")
2. What colour of coat did he buy? (as if he bought a colour)
3. A coat of what colour did he buy? (seems to be precise, but is it correct?)
4. What colour did he buy a coat? (?)
5. What colour did he buy a coat of? (???)
6. Of what colour did he buy a coat? (this should be wrong)
8. He bought a coat of what colour? (?)
7. ???
Thank you in advance for all your comments.