Improve the bracketed part of the sentence, if necessary: He has painted that picture so often that he can do it with his (eyes closed).

Introduction / Context:
This sentence improvement question checks whether the underlined or bracketed phrase is already correct or needs replacement. The sentence describes someone who has painted a picture so many times that he can now paint it very easily, even without looking, which is a common English idiom.

Given Data / Assumptions:

• The original sentence is: “He has painted that picture so often that he can do it with his eyes closed.”
• The phrase in brackets is “eyes closed”.
• Four options are given, including “No improvement”.
• We assume the sentence is intended to use a standard idiomatic expression.

Concept / Approach:
The idiom “with one's eyes closed” means to do something very easily, almost automatically, because of a lot of practice. The phrase “with his eyes closed” is therefore both grammatically correct and idiomatically perfect in this sentence. Any replacement would either change the meaning or make the sentence awkward.

Step-by-Step Solution:
Understand the meaning: he has practised painting the picture so often that it is very easy for him now.Recognize the idiom “with his eyes closed” which exactly expresses this idea of effortless action.Check option “arms full”: “with his arms full” would mean his hands are occupied with other things; this does not suit the context of painting.Check option “eyes opened”: this is grammatically different and loses the idiomatic meaning of effortless action.Check option “mind blank”: “with his mind blank” would mean he is not thinking, which is not the intended idea.Therefore, the best choice is “No improvement”, since the original expression is already correct.

Verification / Alternative check:
Read the original sentence again: “He has painted that picture so often that he can do it with his eyes closed.” This sounds natural and idiomatic in standard English. Native speakers commonly use this expression to indicate mastery through repetition, so no correction is needed.

Why Other Options Are Wrong:
“Arms full” changes the meaning to carrying something and does not relate to skill. “Eyes opened” is merely literal and removes the idiomatic emphasis on ease. “Mind blank” gives a different idea that he is not thinking, which is unrelated to practice and skill. None of these alternatives improve the sentence.

Common Pitfalls:
Many students think every question must require a change, but in sentence improvement exercises “No improvement” is often correct. The key is to recognise standard idioms and accept them when they are already correct instead of forcing a change.

Final Answer:
The bracketed phrase is already correct, so the answer is No improvement.