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