Como é que se diz isto em Inglês (EUA)? in case you want to be something you can't be such as a cat or dog, and when you want to use a phrase of "want to"

See a translation

I'm not sure I fully understood the question, but I'll try my best to explain ☺️

When you express a wish that is not possible, you use conditional verbs which show a hypothetical situation (an imaginary situation that is not possible) or verbs that show desire. Some examples of conditional verbs are:

- could have
- would have
- if (...) I (would have/will/etc.)

Some verbs that show desire:
- I wish
- I would like

If you want to express a situation that is possible, then you can use 'I want':

Ex:
- I want to be a doctor
- I want to run 5km per day
- I want to go on a diet

There are certain situations in which "I want to be a cat" is more natural, like:

A: What do you want to be for Halloween?
B: I want to be a cat.

I'm sorry English is such a difficult language to learn 😅 There are so many rules that aren't always regular.