Corduroy

[Rosetta has tagged along with Corduroy, Lisa, and Moppy. That is, since the beginning of the episode. It has even been seen onscreen too. Scene first cuts to the ducks.]

Lisa:
The poor ducklings, they are stranded out there.

[Cut to Corduroy]

Corduroy:
[thinking] Why are they not swimming Lisa?

[Lisa approaches to Corduroy.]

Corduroy:
They want to swim. But they can't because the water is so dirty.

Rosetta:
[thinking --and from Corduroy's overalls] It is not only because the water is dirty. It's also because people have been putting dirt into the water.