Final answer:
To correct the sentence using the subjunctive mood, it should be written as "Mr. White insists that his wife keep the door closed." The subjunctive expresses suggestions or requirements and differs from the indicative mood that states facts or opinions.
Step-by-step explanation:
The sentence "Mr. White insists that his wife keeps the door closed." does not use the correct form of the verb for the subjunctive mood, which is a verb mood used to express wishes, suggestions, or requirements, or to state hypothetical or unlikely scenarios. The correct subjunctive mood for this sentence is "Mr. White insists that his wife keep the door closed."
The subjunctive mood is often used in situations that require a degree of uncertainty or non-reality. In contrast, the indicative mood is used for stating facts, opinions, or questions, such as in the statement, "Thousands of women currently serve in the military. When considering the subject/verb agreement, it's important to identify the true subject of the sentence and ensure the verb agrees with it. For example, "The play [with such true witticisms and parables] comes highly recommended," correctly uses the singular verb 'comes' to agree with the singular subject 'play'.