I could lessen you could lessen he could lessen we could lessen you could lessen they could lessen
V-ing form
I could be lessening you could be lessening he could be lessening we could be lessening you could be lessening they could be lessening
Perfect
I could have lessened you could have lessened he could have lessened we could have lessened you could have lessened they could have lessened
V-ing perfect
I could have been lessening you could have been lessening he could have been lessening we could have been lessening you could have been lessening they could have been lessening
Negation
Simple form
I could not lessen you could not lessen he could not lessen we could not lessen you could not lessen they could not lessen
V-ing form
I could not be lessening you could not be lessening he could not be lessening we could not be lessening you could not be lessening they could not be lessening
Perfect
I could not have lessened you could not have lessened he could not have lessened we could not have lessened you could not have lessened they could not have lessened
V-ing perfect
I could not have been lessening you could not have been lessening he could not have been lessening we could not have been lessening you could not have been lessening they could not have been lessening
Interrogative form
Simple form
could I lessen? could you lessen? could he lessen? could we lessen? could you lessen? could they lessen?
V-ing form
could I be lessening? could you be lessening? could he be lessening? could we be lessening? could you be lessening? could they be lessening?
Perfect
could I have lessened? could you have lessened? could he have lessened? could we have lessened? could you have lessened? could they have lessened?
V-ing perfect
could I have been lessening? could you have been lessening? could he have been lessening? could we have been lessening? could you have been lessening? could they have been lessening?
Interro-negative form
Simple form
could I not lessen? could you not lessen? could he not lessen? could we not lessen? could you not lessen? could they not lessen?
V-ing form
could I not be lessening? could you not be lessening? could he not be lessening? could we not be lessening? could you not be lessening? could they not be lessening?
Perfect
could I not have lessened? could you not have lessened? could he not have lessened? could we not have lessened? could you not have lessened? could they not have lessened?
V-ing perfect
could I not have been lessening? could you not have been lessening? could he not have been lessening? could we not have been lessening? could you not have been lessening? could they not have been lessening?