Which sentence is written in the conditional mood?

Question

Responses

Why aren't you babysitting tonight?
Why aren't you babysitting tonight?

I can sing well enough, so I'll join the chorus.
I can sing well enough, so I'll join the chorus.

If I don't gain enough experience, I can't be a lifeguard this summer.
If I don't gain enough experience, I can't be a lifeguard this summer.

Since I have to mail this letter, let's stop at the post office.

Answer 1

The sentence written in the conditional mood is:

If I don't gain enough experience, I can't be a lifeguard this summer.

This sentence expresses a condition (not gaining enough experience) that affects the outcome (not being able to be a lifeguard).