I can pick you can pick he can pick we can pick you can pick they can pick
V-ing form
I can be picking you can be picking he can be picking we can be picking you can be picking they can be picking
Perfect
I can have picked you can have picked he can have picked we can have picked you can have picked they can have picked
V-ing perfect
I can have been picking you can have been picking he can have been picking we can have been picking you can have been picking they can have been picking
Negation
Simple form
I cannot pick you cannot pick he cannot pick we cannot pick you cannot pick they cannot pick
V-ing form
I cannot be picking you cannot be picking he cannot be picking we cannot be picking you cannot be picking they cannot be picking
Perfect
I cannot have picked you cannot have picked he cannot have picked we cannot have picked you cannot have picked they cannot have picked
V-ing perfect
I cannot have been picking you cannot have been picking he cannot have been picking we cannot have been picking you cannot have been picking they cannot have been picking
Interrogative form
Simple form
can I pick? can you pick? can he pick? can we pick? can you pick? can they pick?
V-ing form
can I be picking? can you be picking? can he be picking? can we be picking? can you be picking? can they be picking?
Perfect
can I have picked? can you have picked? can he have picked? can we have picked? can you have picked? can they have picked?
V-ing perfect
can I have been picking? can you have been picking? can he have been picking? can we have been picking? can you have been picking? can they have been picking?
Interro-negative form
Simple form
can I not pick? can you not pick? can he not pick? can we not pick? can you not pick? can they not pick?
V-ing form
can I not be picking? can you not be picking? can he not be picking? can we not be picking? can you not be picking? can they not be picking?
Perfect
can I not have picked? can you not have picked? can he not have picked? can we not have picked? can you not have picked? can they not have picked?
V-ing perfect
can I not have been picking? can you not have been picking? can he not have been picking? can we not have been picking? can you not have been picking? can they not have been picking?