- Oh, please don't interrupt the lesson.
- Of course not. I understand.

3 seconds sound clip from the Phantom of the Opera (1943) movie soundboard.

You can hear this line at 00:19:44.750 in the Blu-ray version of the movie.

Quote context

[...]

- Marie, you've been very kind. You've been very patient. You'll be paid, I promise you! Now, please leave me alone.

- It makes me sick to think of all that money doing nobody any good.

- Either I get my money, or out you go! That's my last word, Claudin.

- You are late, Monsieur Claudin. The lesson is almost over.

- I didn't come about that today, mademoiselle.

- She's not in voice today.

- I'll tell Signor Ferretti...

- Oh, please don't interrupt the lesson.

- Of course not. I understand.

- But I must announce the time to Signor Ferretti or he'll keep his students for hours.

- It's 11:00, Signor Ferretti.

- Thank you.

- Mademoiselle, you disappoint me this morning.

- I'm sorry. I'm a little upset.

- If some man is upsetting you, pitch him out of your life. Music is first. Music is everything.

[...]