Sentence improvement (idiom and collocation) — Choose the most appropriate replacement so the sentence becomes natural and grammatically correct: ‘‘Will you kindly open the knot?’’ (focus on the correct verb used with ‘‘knot’’ for competitive English usage).

Given sentence
‘‘Will you kindly open the knot?’’

Concept/Approach
In idiomatic English, the standard collocation is untie a knot, not ‘‘open’’ a knot. We choose the verb that naturally pairs with the noun to convey the intended action.

Reasoning
Use: untie + knot ⇒ ‘‘untie the knot’’ is the accepted phrase.‘‘Open’’ is used with doors, boxes, files, etc., not with knots.

Option analysis
A: untie — Correct collocation: ‘‘untie the knot’’ sounds natural and precise.B: break — ‘‘break the knot’’ implies force or snapping; it changes the meaning.C: loose — Adjective/adverb; the verb form is ‘‘loosen’’; also less idiomatic than ‘‘untie’’.D: No improvement — Original is non-idiomatic; improvement is needed.

Final Answer
untie