「rent, lend, borrow」の違い

The other day somebody came to class and realized she had forgotten her pen. She asked me:
× Can you borrow a pen?
○ Can I borrow a pen? Can you lend me a pen?

• borrow 借りる
• lend 貸す

"Borrow" and "lend" have a direction. The subject of "borrow" is receiving something. The subject of "lend" is giving something.

I was talking about a book with someone. It sounded like an interesting book. The person I was talking to sensed my interest in the book and said:
× I can rent it to you.
○ I can lend it to you.

• rent 賃借［賃貸］する

If you rent something, it means you are a business person. You are earning money by allowing someone to use something that you own. I know that the pronunciation of these two is a little similar. You have to be really careful about "r" and "l".

One student has been collecting notes from class in her notebook. She always punches holes in her paper using the rings in her binder. I had been meaning to get a hole punch, but every time I go to the 100 yen shop or office supply store, I always seem to forget what I wanted to buy.

• hole punch 穴あけ器 (definition from Eijiro on the Web)

This week, though, my memory was working well, and I remembered to get the hole punch.

If you ever visit me at my classroom, I'd be happy to lend you a pen or my hole punch. I'll even lend you a sympathetic ear.

• lend a sympathetic ear 親身になって耳を貸す、同情して話を聞く、じっくり話を聞く (definition from Eijiro on the Web)