Select the most appropriate option to improve the bold part of the sentence.
You must refrain to smoke.
Show answer & explanation
Correct answer: D
Explanation
The verb refrain is a prepositional verb that is traditionally followed by the preposition ‘from’ and a ‘gerund’ (an "-ing" word).
Incorrect: refrain + to + verb
Correct: refrain + from + [verb]ing
Therefore, the corrected sentence is: "You must refrain from smoking."