You should've stayed and helped her with her homework.
5 seconds sound clip from the The Roaring Twenties (1939) movie soundboard.
You can hear this line at 00:20:35 in the DVD version of the movie.
Quote context
[...]
- So long.
- I'll call you. In about two or three years, when you get to be a great big girl.
- Bye.
- You should've stayed and helped her with her homework.
- The word speakeasy begins to appear in our language.
[...]