In the following sentence improvement question, choose the alternative that best improves the bracketed part of the sentence. In case no improvement is needed, select "no improvement": "His shoes ( to cover ) with mud."

Introduction / Context:
This grammar question tests your understanding of subject verb agreement and passive voice. The sentence describes the condition of "his shoes" after they have become muddy. The bracketed phrase must be changed into the correct tense and voice to match the plural subject and the intended meaning of state or result, not action performed by the shoes.

Given Data / Assumptions:

• Original sentence with bracket: "His shoes ( to cover ) with mud."
• The subject "shoes" is plural.
• We want to say that the shoes were in a state of being covered with mud, not that they were covering something else.
• The options provide different verb forms, including passive constructions and a progressive form.

Concept / Approach:
The correct structure here is a passive voice construction describing a resulting state: "His shoes were covered with mud." Since "shoes" is plural, the auxiliary verb must be "were," not "was." The past participle "covered" expresses the state after the action of mud covering the shoes. "Was covered" would agree with a singular subject, and "were covering" would be an active progressive form suggesting that the shoes were covering something else, which is not the intended meaning.

Step-by-Step Solution:
Step 1: Identify the subject: "shoes" is plural. Step 2: Decide on tense and voice: we need a past tense passive to show the shoes ended up covered in mud. Step 3: Form the passive: plural "were" + past participle "covered" = "were covered." Step 4: Insert into the sentence: "His shoes were covered with mud." Step 5: Verify that the sentence now sounds natural and grammatically correct.

Verification / Alternative check:
Test other options: "His shoes was covered with mud" is wrong because "was" does not agree with plural "shoes." "His shoes were covering with mud" is ungrammatical because "covering" normally needs an object ("covering the floor"), not "with mud" in this position, and the meaning changes to an active action by the shoes. "No improvement" cannot be right because "to cover" is an infinitive and does not fit into the sentence as is. Only "were covered" correctly expresses the intended state and matches the subject.

Why Other Options Are Wrong:

• was covered: Uses singular "was," which does not agree with plural "shoes."
• were covering: Changes the meaning to an active continuous action by the shoes and does not combine properly with "with mud."
• no improvement: Leaves the sentence with the bare infinitive "to cover," which is incomplete and ungrammatical in this context.

Common Pitfalls:
Students sometimes forget to adjust the auxiliary verb when changing from singular to plural subjects, leading to errors like "shoes was." Another pitfall is confusing passive and active forms: "were covering" may look similar to "were covered" but has a very different grammatical structure and meaning. Remember that the pattern "were + past participle" is passive, describing what happens to the subject, while "were + -ing form" is active, describing what the subject is doing. Here we need the passive form.

Final Answer:
The correct improvement is were covered, giving the sentence: His shoes were covered with mud.