7. What do you think?

Corrected sentence options:

• When will you finish
• When you are going to finish
• When you are finishing

The most grammatically correct and commonly used phrasing among the options provided is 'When will you finish'. This uses the future simple tense, which is appropriate for asking about a future event. 'When you are going to finish' is also grammatically correct and conveys a similar meaning, but 'will' is often more direct in this context. 'When you are finishing' typically refers to something happening at the very moment of speaking or to a continuous action in the future, which is less likely to be the intended meaning for a general inquiry about completion.

Answer: When will you finish