How to check if a civilian is in a city?

I've had a go, but can't figure out how to check if a Worker is stationed in a city. A worker can't garrison, so I can't use GetGarrisonedUnit(), so I imagine I might need to check if the Worker is in the same plot as a city, but for that I'm unsure how to get it done. I'd appreciate some help on this. Thanks.

Also, I struggle to understand how to check if a specific civ has researched a specific tech/belongs to a specific team and I'm not able to find any existing examples on the forums.