1. Look for the "-ing" ending: The most obvious clue is the "-ing" suffix.
2. Check the function in the sentence:
* Subject: The gerund is the subject of the sentence.
* Example: *Swimming* is a great exercise.
* Object: The gerund is the object of a verb or preposition.
* Example: I enjoy *hiking* in the mountains.
* Example: He's afraid of *public speaking*.
* Object of a preposition: The gerund follows a preposition.
* Example: He left without *saying* goodbye.
* Appositive: The gerund renames another noun.
* Example: His favorite hobby, *fishing*, relaxes him.
3. Consider if it can be replaced with a noun: If you can replace the "-ing" word with a noun, it's likely a gerund.
Examples:
* Correct: *Swimming* is a great exercise. (can be replaced with "The activity of swimming")
* Incorrect: *Swimming* in the pool. (This is a verb phrase, not a gerund)
Note:
* Don't confuse gerunds with present participles. Present participles act as adjectives or part of a verb phrase.
* Example: *Singing* birds filled the air. (*Singing* modifies "birds").
* A gerund can sometimes be part of a longer phrase, such as "eating a hamburger" or "working on the project."
In summary, a verbal noun or gerund is an "-ing" word that acts like a noun in a sentence. Look for the "-ing" ending and consider the function of the word within the sentence to identify it.