The teacher, as well as his students … working very hard.

Analyze the question

This tests subject-verb agreement, specifically what happens when a subject is followed by a phrase like "as well as."

Explain the concept

Phrases such as as well as, along with, together with, in addition to, and besides do not make a subject plural. They are parenthetical, meaning they only add extra information. The verb agrees with the main subject, which comes before the phrase.

Show the solution

• Main subject: The teacher (singular)
• Parenthetical phrase: as well as his students (ignore it when choosing the verb)
• So the sentence reads: The teacher ... is working very hard.

Checking the options:

• A. is – singular, present continuous, agrees with "teacher" ✔
• B. have been – plural/perfect form, does not agree ✘
• C. are – plural, does not agree ✘
• D. were – plural past form, does not agree ✘

Correct sentence: The teacher, as well as his students, is working very hard.

Tip

Mentally remove the phrase between the commas: "The teacher ... is working." If the sentence sounds right without it, the verb is correct. Remember: "as well as" ≠ "and." Only and creates a plural subject (e.g., "The teacher and his students are working hard").