Look. It’s very simple.

It’s = It is

That’s all there is to it. If you aren’t sure if something should be “its” or “it’s,” just substitute “it is.” If that doesn’t make sense, then lose the apostrophe.

I won’t get into speculation as to when or how our schools stopped teaching basic grammar, especially the past participle form of verbs. I held my tongue for years when people would say things like “He had drank too much,” figuring they thought the word “drunk” might be misunderstood in that context. But since I heard an NPR reporter actually say “We had went earlier,” I guess we can safely call game over. If you never learned that every verb has three forms and not just two*, you’re probably not going to learn them all now.

But it’s and its? Simple. Don’t make me explain this again, okay?

*Yes, I know, in some verbs the past and past participle are the same, i.e., "jump, jumped, has jumped.” My point is, in some verbs they’re not the same and if you claim to speak English you should know that.