English Trainer Chronicles: Put to sleep

Learner: My journey today is not very good. I will go to the dentist in two hours.
Me: Why?
Learner: I have cavities.
Me: Oh. Sorry to hear that. How do you feel about going to the dentist?
Learner: It's not good, but it's okay. The dentist will sleep my tooth.
Me: Sorry, but that's not correct. The dentist can't sleep your tooth.

I introduce the expression "put to sleep."

Me: Now, please repeat.
Learner: The dentist will put my tooth to sleep.

We talk about how it's not really the tooth, but the nerves. And that the procedure is called a root canal.

Then I have the brilliant idea of introducing the other meaning of "put to sleep."

Me: Do you have a pet?
Learner: I had a cat.
Me: Well, you know when the cat is very, very sick and it won't be okay?
Learner: Yes. My cat was very, very sick. And now it's sleeping forever because it's die!
Me: (After correcting "It's die!") So, you put your cat to sleep.
Learner: I put my cat to sleep because it was very, very sick.
Me: Yes.
Learner: Yes.


Learner: But for me, it's only the tooth?
Me: Yes.