I can crowd you can crowd he can crowd we can crowd you can crowd they can crowd
V-ing form
I can be crowding you can be crowding he can be crowding we can be crowding you can be crowding they can be crowding
Perfect
I can have crowded you can have crowded he can have crowded we can have crowded you can have crowded they can have crowded
V-ing perfect
I can have been crowding you can have been crowding he can have been crowding we can have been crowding you can have been crowding they can have been crowding
Negation
Simple form
I cannot crowd you cannot crowd he cannot crowd we cannot crowd you cannot crowd they cannot crowd
V-ing form
I cannot be crowding you cannot be crowding he cannot be crowding we cannot be crowding you cannot be crowding they cannot be crowding
Perfect
I cannot have crowded you cannot have crowded he cannot have crowded we cannot have crowded you cannot have crowded they cannot have crowded
V-ing perfect
I cannot have been crowding you cannot have been crowding he cannot have been crowding we cannot have been crowding you cannot have been crowding they cannot have been crowding
Interrogative form
Simple form
can I crowd? can you crowd? can he crowd? can we crowd? can you crowd? can they crowd?
V-ing form
can I be crowding? can you be crowding? can he be crowding? can we be crowding? can you be crowding? can they be crowding?
Perfect
can I have crowded? can you have crowded? can he have crowded? can we have crowded? can you have crowded? can they have crowded?
V-ing perfect
can I have been crowding? can you have been crowding? can he have been crowding? can we have been crowding? can you have been crowding? can they have been crowding?
Interro-negative form
Simple form
can I not crowd? can you not crowd? can he not crowd? can we not crowd? can you not crowd? can they not crowd?
V-ing form
can I not be crowding? can you not be crowding? can he not be crowding? can we not be crowding? can you not be crowding? can they not be crowding?
Perfect
can I not have crowded? can you not have crowded? can he not have crowded? can we not have crowded? can you not have crowded? can they not have crowded?
V-ing perfect
can I not have been crowding? can you not have been crowding? can he not have been crowding? can we not have been crowding? can you not have been crowding? can they not have been crowding?