Commonly misused words and The Avengers

Their-possessive form of they
“It’s their problem now, Cap. I have nothing to do with the clean up, that's all the city's problem.” Tony said after defeating the Doombot invasion.

There-indicates location
“Hulk, quick! Over there by the fire hydrant, smash that robot!” Steve instructed the Hulk during the invasion.

They’re-They are
“They’re not seriously going to do that, are they?” Natasha asked Phil as Bruce and Tony prepped to launch homemade fireworks from the balcony.

And now, all three together!
“Over there, they’re about to learn their lesson-don’t piss off the Hulk!” Clint said to Natasha during the battle. Really, people needed to learn-don't piss off the hulk, you just end up getting smashed.