Those awful Gerunds !!!!!

[Chanounie]

Can you tell me and explain why please if this sentence has a gerund ? :
Watching television can be a waste of time. Thank you. These gerunds drive me up the wall !!!!!

[Casiopea]

Gerunds are nouns. Nouns function as subject and objects:

Swimming is fun. <subject>
I like swimming. <object>

Nouns can be replaced by pronouns, like this,

It is fun. <pronoun: It = Swimming>
I like it. <pronoun: it = swimming>

Now let's look at your example sentence:

Watching television can be a waste of time.

Question 1: What's the subject?
Question 2: Can we replace the subject with a pronoun?

If you answer "Yes" to both questions, then "Watching television" is a gerund.

[Chanounie]

Thanks again Casiopea.