can whistle
Regular verb: whistle - whistled- whistled

Affirmation 	
Simple form 	V-ing form 	Perfect 	V-ing perfect 	
I can whistle
you can whistle
he can whistle
we can whistle
you can whistle
they can whistle 	I can be whistling
you can be whistling
he can be whistling
we can be whistling
you can be whistling
they can be whistling	I can have whistled
you can have whistled
he can have whistled
we can have whistled
you can have whistled
they can have whistled	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 	V-ing form 	Perfect 	V-ing perfect 	
I cannot whistle
you cannot whistle
he cannot whistle
we cannot whistle
you cannot whistle
they cannot whistle 	I cannot be whistling
you cannot be whistling
he cannot be whistling
we cannot be whistling
you cannot be whistling
they cannot be whistling	I cannot have whistled
you cannot have whistled
he cannot have whistled
we cannot have whistled
you cannot have whistled
they cannot have whistled	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 	V-ing form 	Perfect 	V-ing perfect 	
can I whistle?
can you whistle?
can he whistle?
can we whistle?
can you whistle?
can they whistle? 	can I be whistling?
can you be whistling?
can he be whistling?
can we be whistling?
can you be whistling?
can they be whistling? 	can I have whistled?
can you have whistled?
can he have whistled?
can we have whistled?
can you have whistled?
can they have whistled? 	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 	V-ing form 	Perfect 	V-ing perfect 	
can I not whistle?
can you not whistle?
can he not whistle?
can we not whistle?
can you not whistle?
can they not whistle? 	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? 	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? 	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?