"the" doesn't have to come in front of "rain"? How about "snow", "sunshine"?

What is the difference between "have a crush on" and "like"?

"Having a crush on someone" specifically refers to admiring someone in a romantic way, and likely wanting a romantic relationship with them. "Liking" someone can have the same meaning, but not always. Like can also be used to express "liking" someone in general, and not in a romantic way. Ex: I have a crush on a boy at school, I want him to be my boyfriend. Ex: I like the girl who lives next to me, I'm thinking on asking her on a date. Ex: I like my teacher, she is kind.

In what circumstances can I use the word "indeed"? Can you show me some examples?

The word "indeed" is usually used to show agreement with a previous statement that was made or to emphasize a point. Ex: Indeed, it is a hot day. Ex: She is smart indeed.

Does "biggest" here mean "greatest"? Because I think BTS is not the largest group with the most members.

You are almost correct! "Biggest" in this context means "extremely popular," "important" or "well-known." Ellen uses "biggest" so that her audience can grasp the idea of just how popular BTS is all over the world. Ex: He is the biggest star in the world right now. Ex: Michael Jordan was one of the biggest basketball players for the Chicago Bulls. He is still popular to this day.

I know "county" is an administrative unit in the United States, but what makes it different from "city" or town"?

A county is the biggest political and administrative jurisdiction (i.e. the biggest local government district) within a state in America. Most states and territories have at least two types of local government: counties (which are the biggest) and municipalities (otherwise known as cities, which are smaller). Sometimes, counties are further divided into townships (which are similar to towns). Thus, you can consider the order to be: state > county > municipality. Ex: The county has lifted its mask mandate. Ex: The county police have jurisdiction over all the townships in the area.

What's the main difference between "squash" and "squish?"

To "squash" something means to crush or squeeze something with a force so that it becomes flat or out of shape. To "squish" something means to crush something so that it's soft or clenched. "Squash" is often used when you talk about flattening or crushing something, and "squish" is often used with things that are soft. Ex: You have to squash and flatten the cans before you recycle them. Ex: Don't let the eggs squish the strawberries in the bag otherwise they'll bruise.