Conjugation verb stiffen up

Present

• I stiffen
• you stiffen
• he/she/it stiffens
• we stiffen
• you stiffen
• they stiffen

Preterite

• I stiffened
• you stiffened
• he/she/it stiffened
• we stiffened
• you stiffened
• they stiffened

Present continuous

• I am stiffening
• you are stiffening
• he/she/it is stiffening
• we are stiffening
• you are stiffening
• they are stiffening

Present perfect

• I have stiffened
• you have stiffened
• he/she/it has stiffened
• we have stiffened
• you have stiffened
• they have stiffened

Future

• I will stiffen
• you will stiffen
• he/she/it will stiffen
• we will stiffen
• you will stiffen
• they will stiffen

Future perfect

• I will have stiffened
• you will have stiffened
• he/she/it will have stiffened
• we will have stiffened
• you will have stiffened
• they will have stiffened

Past continous

• I was stiffening
• you were stiffening
• he/she/it was stiffening
• we were stiffening
• you were stiffening
• they were stiffening

Past perfect

• I had stiffened
• you had stiffened
• he/she/it had stiffened
• we had stiffened
• you had stiffened
• they had stiffened

Future continuous

• I will be stiffening
• you will be stiffening
• he/she/it will be stiffening
• we will be stiffening
• you will be stiffening
• they will be stiffening

Present perfect continuous

• I have been stiffening
• you have been stiffening
• he/she/it has been stiffening
• we have been stiffening
• you have been stiffening
• they have been stiffening

Past perfect continuous

• I had been stiffening
• you had been stiffening
• he/she/it had been stiffening
• we had been stiffening
• you had been stiffening
• they had been stiffening

Future perfect continuous

• I will have been stiffening
• you will have been stiffening
• he/she/it will have been stiffening
• we will have been stiffening
• you will have been stiffening
• they will have been stiffening

Present

• stiffening

Past

• stiffened

• having stiffened