He can swim, can't he?

1.   ?    Sure.
2.   ?    Yes, he can.
3.   ?    Certainly.

Do you mind speaking up?

1.   ?    Don't worry about it.
2.   ?    No, I don't.
3.   ?    Oh, sure, I can do that.

Open the door please. Someone's there.

1.   ?    Don't worry about it.
2.   ?    Okay.
3.   ?    Yes, he can.

Can you make two photocopies?

1.   ?    Certainly.
2.   ?    Yes, he can.
3.   ?    No, I don't.

Could you turn the volume down?

1.   ?    Yes, he can.
2.   ?    Don't worry about it.
3.   ?    Sorry, am I bothering you?

You don't speak Russian, do you?

1.   ?    Yes, he can.
2.   ?    No, I don't.
3.   ?    Certainly.

I'm very sorry. It won't happen again.

1.   ?    Don't worry about it.
2.   ?    Oh, sure, I can do that.
3.   ?    Certainly

Can you take the phone?

1.   ?    No, I don't.
2.   ?    Don't worry about it.
3.   ?    Sure.