I stiffen you stiffen he stiffens we stiffen you stiffen they stiffen
Present continuous
I am stiffening you are stiffening he is stiffening we are stiffening you are stiffening they are stiffening
Preterite
I stiffened you stiffened he stiffened we stiffened you stiffened they stiffened
Preterite continuous
I was stiffening you were stiffening he was stiffening we were stiffening you were stiffening they were stiffening
Present perfect
I have stiffened you have stiffened he has stiffened we have stiffened you have stiffened they have stiffened
Present perfect continuous
I have been stiffening you have been stiffening he has been stiffening we have been stiffening you have been stiffening they have been stiffening
Pluperfect
I had stiffened you had stiffened he had stiffened we had stiffened you had stiffened they had stiffened
Pluperfect continuous
I had been stiffening you had been stiffening he had been stiffening we had been stiffening you had been stiffening they had been stiffening
Future
I will stiffen you will stiffen he will stiffen we will stiffen you will stiffen they will stiffen
Future continuous
I will be stiffening you will be stiffening he will be stiffening we will be stiffening you will be stiffening they will be stiffening
Future perfect
I will have stiffened you will have stiffened he will have stiffened we will have stiffened you will have stiffened they will have stiffened
Future perfect continuous
I will have been stiffening you will have been stiffening he will have been stiffening we will have been stiffening you will have been stiffening they will have been stiffening
Conditional
Present
I would stiffen you would stiffen he would stiffen we would stiffen you would stiffen they would stiffen
Present continuous
I would be stiffening you would be stiffening he would be stiffening we would be stiffening you would be stiffening they would be stiffening
Past
I would have stiffened you would have stiffened he would have stiffened we would have stiffened you would have stiffened they would have stiffened
Past continuous
I would have been stiffening you would have been stiffening he would have been stiffening we would have been stiffening you would have been stiffening they would have been stiffening