Sentence correction, also referred to as sentence improvement, is an important grammatical exercise in which a sentence is supplied with a word or phrase that requires correction for accuracy and clarity. It is a process that entails the detection and correction of errors in terms of tense and time, subject-verb agreement, correct usage of articles, adverb and adjective placement, and proper forms of verbs. Learning sentence correction not only enriches an individual's grammar, but also hones his skills in forming efficient and lucid sentences. In U.S. competitive exams like the SAT, ACT, and GRE, sentence correction questions probe a candidate's control over both grammar and the structure of the sentence. A firm understanding of sentence improvement techniques has the potential to greatly enhance test performance by allowing candidates to easily and effectively recognize and correct mistakes.

Example of English Grammar Sentence Correction: 

• The kakistocracy have require the attention of the citizens of a country. (Incorrect)
• The Kakistocracy requires the attention of the citizens of a country. (Correct)

Types of Sentence Improvement Asked in Exam

1. Highlighted sentence improvement: The category of sentence improvement where the incorrect part of the sentence is ‘Highlighted’. For instance, You’ve made a spelling mistake here. Rub it off and correct it, please.
2. Blank sentence improvement: The category of sentence improvement where the incorrect grammatical part of the sentence is given in blank.  For instance, The train is running late after time.
3. Blank sentence improvement: the category of sentence improvement is where the incorrect part of the sentence is given in (brackets). For instance, Each and everyone (are) interested in the cricket match.

Rules and Cases of English Grammar Sentence Correction

Rule #1: Subject – Verb Agreement As the name says itself, the verb used in the sentence should be in accordance with the subject. Both should be either plural or singular at the same time.

Example: 

• The girl was reading. (Singular)

• The girls were reading. (Plural)

In the case of collective nouns (like police, army, herd, etc.), the verb used is singular.

Example:

• The army is a collection for soldiers. 
• Despite the riots, the police did not protect the citizens.

Q. A part of the sentence is underlined. Below are given alternatives to the underlined part which may improve the sentence. Choose the correct alternative. In case no improvement is needed, choose ‘No Improvement’.

The list of items are in my bag.

1. Would
2. Were
3. Is
4. No Improvement

Ans: The correct answer is 3. The list is the subject here and a singular subject takes a singular verb. Therefore, the correct sentence is: The list of items is in my bag.

Rule #2: Conjunctions (Subjects connected by ‘BY’, ‘AND’, ‘OR’)

Example:

• Point A and Point B are adjacent to each other in the diagram.

• Sam or Stella is planning to study tonight. 

Q. Martin and Martha is planning to take a vacation after a long time.

1. Are planning
2. Have planning
3. Am planning
4. No improvement

Ans: The correct answer is option 1) i.e. ‘Are planning’ The sentence has two subjects, ‘Martin’ and ‘Martha’. Both the subjects are conjoined by ‘and’ as a conjunction. The subjects are plural in number. Plural subjects = Plural verbs Hence, the correct sentence will be: Martin and Martha are planning to take a vacation after a long time.

Rule #3: If the sentence begins with each/anyone/everyone, a singular verb is used.

Example: Each one of us is deciding upon the matter.

Q. A part of the sentence is underlined. Below are given alternatives to the underlined part which may improve the sentence. Choose the correct alternative. In case no improvement is needed, choose ‘No Improvement.

Everyone remained silent and no one steps up the plate for the change.

1. Has remained
2. Am remained
3. Remains
4. No improvement

Ans:

• The correct answer is option 3) i.e. ‘remains’
• The subject of the sentence is ‘Singular indefinite pronoun’.
• ‘Everyone’ always takes a singular verb with it.
• As this is a sentence in simple present tense, hence, the sentence will follow the rule of Singular subject = Singular verb.
• Thus, the correct sentence will be: Everyone remains silent and no one steps up the plate for the change.

Rule #4: For the sentences that contain ‘either/or’ and ‘neither/nor’ pairs, the verb used will be singular if both the subjects are singular. In case one or both the subjects are plural, the plural verb is used.

Example:

• Either he or she smirks when the teacher discusses politics.

• Either he or they smirk when the teacher discusses politics.

• Neither he nor she smirks when the teacher discusses politics.

• Neither he or they smirk when the teacher discusses politics.

Q. A part of the sentence is bracketed. Below are given alternatives to the underlined part which may improve the sentence. Choose the correct alternative. In case no improvement is needed, choose ‘No Improvement.

Either Ham or egg (are prepared) for breakfast this morning.

1. Is prepared
2. Have prepared
3. Has prepared
4. No improvement

Ans:

• The correct answer is option 1) i.e. ‘Is prepared’
• The sentence given has the case of ‘Either/or’.
• In the case of ‘Either/or’, there is always a choice of subject out of two given.
• Despite two subjects in a sentence, only singular subject is considered.
• Thus and so, the correct sentence will be: Either Ham or eggis prepared for breakfast this morning.

Example: Either Ham or eggs (is prepared) for breakfast this morning.

 

1. Has prepared
2. Would prepare
3. Are prepared
4. No Improvement

Ans:

• The correct answer is option 3) i.e. ‘Are prepared’
• The sentence given has the case of ‘Either/or’.
• In the case of ‘Either/or’, if the subject close to the verb is plural, then the plural subject takes plural verb.
• Thus and so, the correct sentence will be: Either Ham or eggs are prepared for breakfast this morning.

Rule #5: Often, there arises confusion between the usage of ‘I’ and ‘me’.

Examples:

• Chris, Stepheny and I are good friends. 

• Chris and I are good friends. 

Q. A sentence/a part of the sentence is underlined. Four alternatives are given to the underlined part which will improve the meaning of the sentence. Choose the correct alternative and click the button corresponding to it. In case no improvement is needed, click the option corresponding to ‘No improvement’.

My father, mother and (me) went to the market.

1. My father, mother and I
2. Me father, me mother and me
3. Mine father, mine mother and we
4. No Improvement

Ans: 

• The correct answer is option 1) i.e. ‘My father, mother and I’
• The personal pronoun, ‘I’ is an objective case of pronoun which means that we always use it after the verb.
• Hence, options 2 and 3 are deleted
• Since, ‘I’ is a subject pronoun; we use it before the verb ‘went’ here.
• Thus, the correct sentence will be: My father, mother and I

Rule #6: Sometimes, there is redundancy in the sentence. In other words, the same thing is written twice in a single statement. Most of the times, you can spot such errors easily.

Example:

• I returned back from Goa. (Incorrect)
• I came back from Goa. (Correct)

Q. A sentence/a part of the sentence is bracketed. Four alternatives are given to the underlined part which will improve the meaning of the sentence. Choose the correct alternative and click the button corresponding to it. In case no improvement is needed, click the option corresponding to ‘No improvement’.

I, along with my friends, (discussed about) the chapter with our teacher.

1. Discussed with
2. Discussed to
3. Discussed
4. No improvement

Ans:

• The correct is answer is option 3) i.e. ‘Discussed’
• There are certain verbs which do not take any preposition along with them.
• For e.g.:- discuss, explain, describe, near, enter, visit, attend, etc.

Rule #7: Errors in Modifiers As you can guess from the name itself, modifiers ‘modify’ the subject. So, where do you think should the modifiers be placed? Yes, they need to be placed next to the subject it modifies.

Example:

• Sitting in the garden, a scorpion stung her.
• (Here, you can’t figure out who is sitting in the garden- the scorpion or the girl. This is an incorrect way. )
• The correct way would be: Sitting in the garden, she was stung by a scorpion.

Q. A sentence/a part of the sentence is bracketed. Four alternatives are given to the underlined part which will improve the meaning of the sentence. Choose the correct alternative and click the button corresponding to it. In case no improvement is needed, click the option corresponding to ‘No improvement’.

When being eight years old, my father gave me a pony for Christmas.

1. When was I
2. When I was
3. Once I was
4. No improvement

Ans:

• The correct answer is option 2) i.e. ‘When I was’
• To communicate ideas clearly, a modifier should be placed directly next to the word it is supposed to modify.
• The modifier should clearly refer to a specific word in the sentence.
• When I was eight years old, my father gave me a pony for Christmas.

Rule #8: Wrong Comparisons Sometimes, the comparisons are made between dissimilar things or in an incorrect way.

Example:

• John is wiser than all men. (Incorrect way)
• John is wiser than all other men. (Correct way- John needs to be excluded from the rest of the same category.)

In the above example, comparative degree is used. But in case of superlative degree, the person/thing compared is included in the rest of the class. E.g. John is the strongest of all men.

Q. A sentence/a part of the sentence is underlined. Four alternatives are given to the underlined part which will improve the meaning of the sentence. Choose the correct alternative and click the button corresponding to it. In case no improvement is needed, click the option corresponding to ‘No improvement’.

Sunita is the wisest and honest teller in the wisest and honester

1. the wisest and most honest
2. the wisest and more honest
3. No Improvement

Ans: Correct option – 2 Since the adjective ‘honest’ comes after the adjective ‘wisest’ in the given sentence, we will replace honest with ‘most honest’ as all the adjectives which refer to the same noun should be in the same degree of comparison. The adjectives ‘honester’ and ‘more honest’ belong to the comparative degree of adjectives and hence cannot be used with the adjective in the superlative degree, i.e., ‘wisest’.

Correct Sentence: Sunita is the wisest and most honest teller in the bank.

Rule #9: Error in Diction: A diction error refers to the error in choice of words/phrases. At other times, even some idioms occur in sentences in an incorrect way.

Common pair of words and phrases where you may face diction error are:

• affect v/s effect (E.g. the effect of the decision, ..affect the outcome)
• adapt v/s adopt
• argue against v/s argue with
• later v/s latter
• lay v/s lie
• few v/s less (E.g. less water left.., ..few students in the class)

In summary, sentence correction is a vital skill for any candidate sitting for U.S. competitive exams such as the SAT, ACT, and GRE. An in-depth knowledge of grammar principles, such as subject-verb agreement, use of conjunctions, modifier position, and appropriate diction, increases a candidate's capability to detect and correct errors efficiently. Sentence correction practice not only enhances grammatical understanding but also confidence in constructing accurate and meaningful sentences. Regular practice of sentence improvement techniques can drastically improve performance on tests by enabling the test-taker to approach language-based questions with ease and accuracy.