undress -> раздевать
Образование времен: Субъект подвергается (Пассив, или иначе страдательный залог)
  Past - ПрошлоеPresent - НастоящееFuture - Будущее
Факт - Simple
I/he/she/itwe/you/they
was undressedwere undressed
---
was not undressedwere not undressed
wasn't undressedweren't undressed
Ihe/she/itwe/you/they
am undressedis undressedare undressed
---
am not undressedis not undressedare not undressed
 isn't undressedare'nt undressed
I/he/she/it/we/you/they
will be undressed
---
will not be undressed
won't be undressed
Процесс - Continuous
I/he/she/itwe/you/they
was being undressedwere being undressed
---
was not being undressedwere not being undressed
wasn't being undressedweren't being undressed
Ihe/she/itwe/you/they
am being undressedis being undressedare being undressed
---
am not being undressedis not being undressedare not being undressed
 isn't being undressedare'nt being undressed
Завершенность - Perfect
I/he/she/it/we/you/they
had been undressed
---
had not been undressed
hadn't been undressed
I/we/you/theyhe/she/it
have undressedhas undressed
---
have not undressedhas not undressed
haven't undressedhasn't undressed
I/he/she/it/we/you/they
will have been undressed
---
will not have been undressed
won't have been undressed
Вместо отсутствующих форм Perfect Continuous употребляются формы Perfect
undress -> раздевать