Regular verb: lengthen - lengthened - lengthened
Simple form | V-ing form |
I must lengthen you must lengthen he must lengthen we must lengthen you must lengthen they must lengthen | I must be lengthening you must be lengthening he must be lengthening we must be lengthening you must be lengthening they must be lengthening |
Perfect | V-ing perfect |
I must have lengthened you must have lengthened he must have lengthened we must have lengthened you must have lengthened they must have lengthened | I must have been lengthening you must have been lengthening he must have been lengthening we must have been lengthening you must have been lengthening they must have been lengthening |
Simple form | V-ing form |
I must not lengthen you must not lengthen he must not lengthen we must not lengthen you must not lengthen they must not lengthen | I must not be lengthening you must not be lengthening he must not be lengthening we must not be lengthening you must not be lengthening they must not be lengthening |
Perfect | V-ing perfect |
I must not have lengthened you must not have lengthened he must not have lengthened we must not have lengthened you must not have lengthened they must not have lengthened | I must not have been lengthening you must not have been lengthening he must not have been lengthening we must not have been lengthening you must not have been lengthening they must not have been lengthening |
Simple form | V-ing form |
must I lengthen? must you lengthen? must he lengthen? must we lengthen? must you lengthen? must they lengthen? | must I be lengthening? must you be lengthening? must he be lengthening? must we be lengthening? must you be lengthening? must they be lengthening? |
Perfect | V-ing perfect |
must I have lengthened? must you have lengthened? must he have lengthened? must we have lengthened? must you have lengthened? must they have lengthened? | must I have been lengthening? must you have been lengthening? must he have been lengthening? must we have been lengthening? must you have been lengthening? must they have been lengthening? |
Simple form | V-ing form |
must I not lengthen? must you not lengthen? must he not lengthen? must we not lengthen? must you not lengthen? must they not lengthen? | must I not be lengthening? must you not be lengthening? must he not be lengthening? must we not be lengthening? must you not be lengthening? must they not be lengthening? |
Perfect | V-ing perfect |
must I not have lengthened? must you not have lengthened? must he not have lengthened? must we not have lengthened? must you not have lengthened? must they not have lengthened? | must I not have been lengthening? must you not have been lengthening? must he not have been lengthening? must we not have been lengthening? must you not have been lengthening? must they not have been lengthening? |