I can whistle you can whistle he can whistle we can whistle you can whistle they can whistle
V-ing form
I can be whistling you can be whistling he can be whistling we can be whistling you can be whistling they can be whistling
Perfect
I can have whistled you can have whistled he can have whistled we can have whistled you can have whistled they can have whistled
V-ing perfect
I can have been whistling you can have been whistling he can have been whistling we can have been whistling you can have been whistling they can have been whistling
Negation
Simple form
I cannot whistle you cannot whistle he cannot whistle we cannot whistle you cannot whistle they cannot whistle
V-ing form
I cannot be whistling you cannot be whistling he cannot be whistling we cannot be whistling you cannot be whistling they cannot be whistling
Perfect
I cannot have whistled you cannot have whistled he cannot have whistled we cannot have whistled you cannot have whistled they cannot have whistled
V-ing perfect
I cannot have been whistling you cannot have been whistling he cannot have been whistling we cannot have been whistling you cannot have been whistling they cannot have been whistling
Interrogative form
Simple form
can I whistle? can you whistle? can he whistle? can we whistle? can you whistle? can they whistle?
V-ing form
can I be whistling? can you be whistling? can he be whistling? can we be whistling? can you be whistling? can they be whistling?
Perfect
can I have whistled? can you have whistled? can he have whistled? can we have whistled? can you have whistled? can they have whistled?
V-ing perfect
can I have been whistling? can you have been whistling? can he have been whistling? can we have been whistling? can you have been whistling? can they have been whistling?
Interro-negative form
Simple form
can I not whistle? can you not whistle? can he not whistle? can we not whistle? can you not whistle? can they not whistle?
V-ing form
can I not be whistling? can you not be whistling? can he not be whistling? can we not be whistling? can you not be whistling? can they not be whistling?
Perfect
can I not have whistled? can you not have whistled? can he not have whistled? can we not have whistled? can you not have whistled? can they not have whistled?
V-ing perfect
can I not have been whistling? can you not have been whistling? can he not have been whistling? can we not have been whistling? can you not have been whistling? can they not have been whistling?