I can smooth you can smooth he can smooth we can smooth you can smooth they can smooth
V-ing form
I can be smoothing you can be smoothing he can be smoothing we can be smoothing you can be smoothing they can be smoothing
Perfect
I can have smoothed you can have smoothed he can have smoothed we can have smoothed you can have smoothed they can have smoothed
V-ing perfect
I can have been smoothing you can have been smoothing he can have been smoothing we can have been smoothing you can have been smoothing they can have been smoothing
Negation
Simple form
I cannot smooth you cannot smooth he cannot smooth we cannot smooth you cannot smooth they cannot smooth
V-ing form
I cannot be smoothing you cannot be smoothing he cannot be smoothing we cannot be smoothing you cannot be smoothing they cannot be smoothing
Perfect
I cannot have smoothed you cannot have smoothed he cannot have smoothed we cannot have smoothed you cannot have smoothed they cannot have smoothed
V-ing perfect
I cannot have been smoothing you cannot have been smoothing he cannot have been smoothing we cannot have been smoothing you cannot have been smoothing they cannot have been smoothing
Interrogative form
Simple form
can I smooth? can you smooth? can he smooth? can we smooth? can you smooth? can they smooth?
V-ing form
can I be smoothing? can you be smoothing? can he be smoothing? can we be smoothing? can you be smoothing? can they be smoothing?
Perfect
can I have smoothed? can you have smoothed? can he have smoothed? can we have smoothed? can you have smoothed? can they have smoothed?
V-ing perfect
can I have been smoothing? can you have been smoothing? can he have been smoothing? can we have been smoothing? can you have been smoothing? can they have been smoothing?
Interro-negative form
Simple form
can I not smooth? can you not smooth? can he not smooth? can we not smooth? can you not smooth? can they not smooth?
V-ing form
can I not be smoothing? can you not be smoothing? can he not be smoothing? can we not be smoothing? can you not be smoothing? can they not be smoothing?
Perfect
can I not have smoothed? can you not have smoothed? can he not have smoothed? can we not have smoothed? can you not have smoothed? can they not have smoothed?
V-ing perfect
can I not have been smoothing? can you not have been smoothing? can he not have been smoothing? can we not have been smoothing? can you not have been smoothing? can they not have been smoothing?