A. NO CHANGE B. one's C. there D. their

Understanding subject-verb agreement is essential for ensuring that sentences are grammatically correct. This principle dictates that a singular subject must have a singular verb, while a plural subject must have a plural verb. In practice, this means paying close attention not only to the subject of the sentence but also to the verb that follows.

For example, in the sentence 'She walks to school,' 'she' is a singular subject, which requires the singular verb 'walks' rather than 'walk.' Similarly, 'They walk to school' utilizes a plural verb 'walk' to agree with the plural subject 'They.'

To apply this concept effectively:

• Identify the subject in the sentence.
• Determine whether the subject is singular or plural.
• Choose the correct form of the verb that matches the subject in number.

Always take the time to double-check your work. Verb forms can sometimes be tricky, and commonly confused pairs such as 'is/are' or 'has/have' often cause errors in subject-verb agreement.

Possessive pronouns indicate ownership and must agree in number and gender with the nouns they modify. Unlike contractions that may sound similar (such as 'it's' for 'it is'), possessive pronouns never contain apostrophes. Some examples include 'his,' 'hers,' 'its,' 'theirs,' 'yours,' etc.

An important note is that 'its' is commonly mistaken due to its close resemblance to 'it's.' Remember, 'its' denotes possession, while 'it's' is a contraction for 'it is' or 'it has.'

To use possessive pronouns correctly:

• Identify the noun that the pronoun is showing possession for.
• Ensure that the pronoun agrees with the noun in number and gender.
• Avoid adding an apostrophe to possessive pronouns.

Consistent practice will aid in the proper usage of possessive pronouns, making your writing clear and grammatically sound.

Sentence correction is a key skill for achieving clarity and precision in writing. It involves identifying errors in sentence structure, grammar, punctuation, and word usage. When correcting sentences, focus on reading the entire sentence first to understand the context, as this will help determine what needs to be changed.

Key steps for sentence correction include:

• Reading the sentence to grasp the overall meaning.
• Looking for common errors such as subject-verb agreement, incorrect pronoun usage, and misplaced modifiers.
• Verifying that the sentence structure is logical and complete.
• Ensuring consistency in tense and point of view.

Remember, the ultimate goal is to convey the intended message in the clearest way possible. With practice, sentence correction can empower you to write with correctness and style.