[amp_mcq option1=”to working” option2=”to have worked” option3=”working” option4=”No improvement” correct=”option4″]
The correct answer is D. No improvement.
The sentence “He stopped to work an hour ago” is grammatically correct and conveys the intended meaning. The word “to” is used in this sentence to indicate that the action of working was stopped in the past. The word “working” is the gerund form of the verb “work,” and it is used in this sentence to describe the action that was stopped.
The other options are incorrect because they do not convey the intended meaning of the sentence. The word “to working” is not a grammatically correct phrase. The word “to have worked” indicates that the action of working was completed in the past, but this is not the meaning that is intended in the sentence. The word “working” is not a grammatically correct sentence on its own.
Therefore, the correct answer is D. No improvement.