Too and Either: Short Responses of Agreement

We use short responses of agreement with most verb tenses and some modal verbs. Below are a few examples.

Verbs
 Examples
 
Use "have" or has" for present perfect
 They have been to Cartagena.
I have, too.

They haven't been to Cartagena.
I haven't either.
 
Use "will" or "won't" for simple future
 Ivone will return the clothes tomorrow.
I will, too.

Ivone won't return the clothes tomorrow.
I won't either.
 
For modal verbs, repeat just the modal ("would" "can" "should" and others)
 I would enjoy playing an instrument.
I would, too.

I wouldn't enjoy playing an instrument.
I wouldn't either.
 
She can stand on her hands.
I can, too.

She can't stand on her hands.
I can't either.