Just like "laundry chute", are there other structures that use the word "chute"? And is it common to see it in America?

What's "long for" mean?

"Long for" is a phrasal verb! To "long for" something or someone means to desire or yearn for them or it greatly. Ex: Sometimes, I long for the old days when I was still friends with her. Ex: I've been longing for a donut this whole week. Ex: She's longing for her boyfriend to return.

Is "dinette" a common word? Is it something similar to "dining room"?

A "dinette" is a small space within a home or living place, usually alongside a kitchen, used for informal/casual. It is often put in places where a large dining room is not possible due to lack of space, as in this tiny house. In simple terms, it acts as a dining room when one does not have space. I would say it is not really that common a word as most people would just refer to it as a small dining room or a casual dining room Ex: The apartment lacks a proper dining room, but has a cozy dinette. Ex: Your dinner is on the table in the dinette.

Just like "laundry chute", are there other structures that use the word "chute"? And is it common to see it in America?

A "chute" is a contraption meant for the rapid transportation of an item from an upper floor of a building to a lower floor of a building. The ones that I can think of are garbage chutes, mail chutes, and laundry chutes. Chutes aren't all that common. You won't see one in every building, but some places and even homes do have them.

What does "down" mean here?

Excellent question. When we use "down" in this way it is not specifically directional. Rather it is used, especially with prepositions, in this case "at", to emphasize that a place is at some distance from you or from somewhere considered to be central. Ex: I'll meet you down at the gym tomorrow. Ex: I heard that he has a house down by the harbour. Ex: I'm going down to the supermarket to buy some milk. Ex: He lives down by the park.

What's the difference between "figure out" and "know"?

Great question. To "figure out" something means to be able to understand something or to solve a problem. To "know" simply means to have knowledge. Here the use of "figure out" lets us know that he is facing a problem in making the right decision about what to make for Monica. Whereas using just "know" lacks that nuance. It is key to note though that if you were to change the sentence and use "know", the general meaning would remain the same, but it would lack work emphasis. Ex: I can't figure out if he's joking. Ex: I don't know if he's joking.