Which sentence shows correct subject-verb agreement?

Concept

In the simple present tense, a finite verb must agree with its subject in person and number.

A singular third-person subject takes the -s/-es form of a regular verb, while a plural subject takes the base form. A present participle ending in -ing needs an auxiliary to form a finite verb phrase.

Application

The subject “teacher” is singular and third person. Therefore the simple-present form of “explain” must be “explains”.

Contrast

• “The teacher explain…” combines a singular third-person subject with the base form “explain”.

• “The teachers explains…” combines a plural subject with the singular form “explains”.

• “The teachers explaining…” uses the participle “explaining” without a finite auxiliary such as “are”.

• “The teacher explains…” combines the singular third-person subject “teacher” with “explains”.

Cross-check

Replace “teacher” with the pronoun “he”: “He explains the lesson” follows the same singular agreement pattern. With the plural “teachers”, the form would be “explain”.

Result

The sentence “The teacher explains the lesson clearly to all the students.” has the required subject-verb agreement.