- Since then, they have never been defeated.
- Then what should we do?

4 seconds sound clip from the Mysterious Footworks of Kung Fu movie soundboard.

You can hear this line at 01:22:57.626 in the Blu-ray version of the movie.

Quote context

[...]

- Mister, you mean you know these men?

- Yes, he does. 20 years ago, he had a fight with 'em.

- A fight?

- Yeah!

- At that time, the Shrimp and the Crab were the champions, fighting for the Emperor.

- They were sent to the north secretly to learn a new technique of kung fu, which they could use to suppress the rebels, especially Shaolin kung fu.

- Many revolutionaries have died at their hands. They're dangerous men. So I...

- In a fight, they like to attack together. They aim for the legs with all their force. It's a most powerful strike. And my legs were broken by them.

- Since then, they have never been defeated.

- Then what should we do?

- I've had a long time to think these 20 years, and it's my opinion that the only way of defeating them is by joining all Shaolin styles into one combined technique.

- Master, why haven't ya done it?

- I can't. I'm too old. And my broken legs can no longer stand it. It's too late.

- Then let me practice.

- Hey, of course you'll practice. That's why I told ya to come here. All right, from now on, you'll learn nothing else.

- I'll perfect your style, just wait and see.

[...]