able 2

@ She understands that she is not able to join the competition. (X)

@ She understands that she can’t join the competition. (V)

Note :

With the verbs of perception (see, hear, smell, etc) and verbs of the mind (understand, decide, remember, etc), we usually use “can” , “can’t”, “could”, “couldn’t” etc .

Examples :

- I can’t see it.

- I can remember it well

- I can smell something here.