Which of the following passive constructions correctly expresses the sentence "The teacher should check the homework"?

Introduction / Context:
This question tests your ability to convert a sentence from active to passive voice while keeping the tense and meaning intact. The original sentence uses a modal verb should and is in the active voice with the teacher as the subject and the homework as the object. You must choose the option that correctly transforms this into passive voice.

Given Data / Assumptions:

• Active sentence: The teacher should check the homework.
• Subject: The teacher.
• Object: The homework.
• Modal + main verb: should check.
• We need a passive structure: modal + be + past participle, with the homework as subject.

Concept / Approach:
To form the passive voice with a modal verb, we keep the modal and follow it with be + past participle. The object becomes the subject, and the original subject is introduced by by if it is mentioned. Thus, The teacher should check the homework becomes The homework should be checked by the teacher. Options that change the modal, the tense, or the structure are not correct conversions.

Step-by-Step Solution:
Step 1: Identify the active structure: Subject (teacher) + modal (should) + base verb (check) + object (the homework).Step 2: Move the object to the subject position: The homework...Step 3: Use the passive pattern with a modal: should be checked.Step 4: Add the original subject with by: by the teacher.Step 5: Combine to form: The homework should be checked by the teacher, which matches option A.

Verification / Alternative check:
Compare each option to the original sentence. Option A preserves the modal should and the meaning that it is a duty or recommendation that the teacher checks the homework. Option B The homework is checked by the teacher shifts the meaning to a general present fact and loses the idea of obligation. Option C describes responsibility in general terms but is not a direct active passive transformation. Option D The homework will be checked by the teacher changes should to will and moves from advisability to future certainty, altering the meaning.

Why Other Options Are Wrong:
Option B uses is checked, which corresponds to a simple present passive, not should check. Option C paraphrases the idea but does not maintain the exact structure or modal verb, so it is not a strict voice transformation. Option D uses will, changing the sense to future action instead of duty or recommendation, so it cannot be considered equivalent to the original sentence.

Common Pitfalls:
Candidates often forget the be in passive constructions with modals and sometimes produce should checked, which is incorrect. Others may accidentally change the modal verb and hence the meaning. Always remember the pattern: modal + be + past participle for passive voice when a modal is involved.

Final Answer:
The correct passive form of The teacher should check the homework is The homework should be checked by the teacher, so option A is correct.