Learn Hardcore Japanese: watasi ha tosyokan de tizu wo karimasu.

は is the topic marker. It tells the listener that “私” (I) is the topic of the sentence—the person we’re talking about. In English you might think of it as setting up “As for me, …” before stating what you do.

Why is で used after 図書館?

で marks the location where an action takes place. Here it indicates that the borrowing action happens at the library. You could translate 図書館で as “at the library.”

What’s the difference between で and に when talking about locations?

で marks where an action occurs (“working at school,” “eating at home”).
に marks a destination (“going to school,” “arriving at the station”) or a point in time (“at 3 o’clock”). They aren’t interchangeable when you’re describing where you do something.

Why is を used after 地図?

を is the direct‐object marker. It shows that 地図 (map) is what you are borrowing. In English terms, “map” is the thing you act upon.

Why does the verb 借ります come at the end of the sentence?

Japanese is generally an SOV (Subject–Object–Verb) language. You first give the subject/topic, then the object, and finally the verb.

What tense and politeness level is 借ります?

借ります is the non‐past (present/future) polite form of 借りる (“to borrow”). It can mean “I borrow” or “I will borrow.”

Can you drop 私 in this sentence? If so, why?

Yes. In Japanese, the subject is often omitted when it’s clear from context. If it’s obvious you’re talking about yourself, you can simply say 図書館で地図を借ります.

Could you replace 借ります with 取ります or もらいます? Would the meaning change?

取ります means “to take” (e.g. grab or pick up) and doesn’t imply borrowing—so it changes the meaning.
もらいます means “to receive” from someone. You could say 図書館で地図をもらいます if the library gives you a free map, but that’s not the usual way to say “I borrow a map.”

How would you turn this sentence into a question?

Change the ending particle from 。 to か:
私は図書館で地図を借りますか？
This means “Do you (or I) borrow a map at the library?” depending on context.