Here are four words that are often confused: apt, likely, prone, liable. Their differences are a bit subtle, but they do mean different things, so you might want to write these in your notebook for future reference.
Apt: Means one is habitually inclined: A frog is apt to gobble up a fly if it gets too close.
Likely: Means one is inclined or tending toward something: She is likely to win (implying the odds are with her).
Prone: Means one is inclined but usually implies undesirable results: He’s prone to tripping.
Liable: Means one is likely to suffer (always undesirable consequences): She’s liable to have accidents (implies probability).
These words have no bearing on other meaning of these words, such as a likely story, he’s lying prone, she’s an apt pupil, not liable for the accident (legally responsible). Being a copyeditor, I’m apt to look for misuse of these words! And I’m likely to find some!