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