Identify the part of the sentence that contains a grammatical error.
A. My grandfather B. is not only C. a fastly runner, D. but also a great swimmer.
Show answer & explanation
Correct answer: C
Explanation
The error lies in the word "fastly". In English, the adjective "fast" is also used as an adverb to describe how an action is done. Therefore, the phrase should be "a fast runner," not "a fastly runner".