I could smoothen you could smoothen he could smoothen we could smoothen you could smoothen they could smoothen
V-ing form
I could be smoothening you could be smoothening he could be smoothening we could be smoothening you could be smoothening they could be smoothening
Perfect
I could have smoothened you could have smoothened he could have smoothened we could have smoothened you could have smoothened they could have smoothened
V-ing perfect
I could have been smoothening you could have been smoothening he could have been smoothening we could have been smoothening you could have been smoothening they could have been smoothening
Negation
Simple form
I could not smoothen you could not smoothen he could not smoothen we could not smoothen you could not smoothen they could not smoothen
V-ing form
I could not be smoothening you could not be smoothening he could not be smoothening we could not be smoothening you could not be smoothening they could not be smoothening
Perfect
I could not have smoothened you could not have smoothened he could not have smoothened we could not have smoothened you could not have smoothened they could not have smoothened
V-ing perfect
I could not have been smoothening you could not have been smoothening he could not have been smoothening we could not have been smoothening you could not have been smoothening they could not have been smoothening
Interrogative form
Simple form
could I smoothen? could you smoothen? could he smoothen? could we smoothen? could you smoothen? could they smoothen?
V-ing form
could I be smoothening? could you be smoothening? could he be smoothening? could we be smoothening? could you be smoothening? could they be smoothening?
Perfect
could I have smoothened? could you have smoothened? could he have smoothened? could we have smoothened? could you have smoothened? could they have smoothened?
V-ing perfect
could I have been smoothening? could you have been smoothening? could he have been smoothening? could we have been smoothening? could you have been smoothening? could they have been smoothening?
Interro-negative form
Simple form
could I not smoothen? could you not smoothen? could he not smoothen? could we not smoothen? could you not smoothen? could they not smoothen?
V-ing form
could I not be smoothening? could you not be smoothening? could he not be smoothening? could we not be smoothening? could you not be smoothening? could they not be smoothening?
Perfect
could I not have smoothened? could you not have smoothened? could he not have smoothened? could we not have smoothened? could you not have smoothened? could they not have smoothened?
V-ing perfect
could I not have been smoothening? could you not have been smoothening? could he not have been smoothening? could we not have been smoothening? could you not have been smoothening? could they not have been smoothening?