English Modals

[tony1_hk]

Certain modal usages in the past - like
- could have for suggestion
- should have for advisability
- would have for hypothetical situation
- would have liked to for desire
imply that the action in question has not been realized.

What does this mean?

[Casiopea]

Welcome, tony.

'that the action ... has not been realized' means, the event didn't happen. 'real' in realize means, true or truth. For example, the following actions did not happen.

You could have walked the dog (but you didn't walk the dog)
You should have done your homework (but you didn't do my homework)
I would have cleaned the house (but I didn't clean the house)
I would have liked to have gone to the party (but I didn't go to the party)

[tony1_hk]

Thank you!
Casiopea helps me a lots to this question.

Other opinions are also welcomed.