English verb conjugation
COULD UNDERSTUDY

Regular verb: understudy - understudied - understudied

Affirmation

Simple form	V-ing form
I could understudy you could understudy he could understudy we could understudy you could understudy they could understudy	I could be understudying you could be understudying he could be understudying we could be understudying you could be understudying they could be understudying
Perfect	V-ing perfect
I could have understudied you could have understudied he could have understudied we could have understudied you could have understudied they could have understudied	I could have been understudying you could have been understudying he could have been understudying we could have been understudying you could have been understudying they could have been understudying

Negation

Simple form	V-ing form
I could not understudy you could not understudy he could not understudy we could not understudy you could not understudy they could not understudy	I could not be understudying you could not be understudying he could not be understudying we could not be understudying you could not be understudying they could not be understudying
Perfect	V-ing perfect
I could not have understudied you could not have understudied he could not have understudied we could not have understudied you could not have understudied they could not have understudied	I could not have been understudying you could not have been understudying he could not have been understudying we could not have been understudying you could not have been understudying they could not have been understudying

Interrogative form

Simple form	V-ing form
could I understudy? could you understudy? could he understudy? could we understudy? could you understudy? could they understudy?	could I be understudying? could you be understudying? could he be understudying? could we be understudying? could you be understudying? could they be understudying?
Perfect	V-ing perfect
could I have understudied? could you have understudied? could he have understudied? could we have understudied? could you have understudied? could they have understudied?	could I have been understudying? could you have been understudying? could he have been understudying? could we have been understudying? could you have been understudying? could they have been understudying?

Interro-negative form

Simple form	V-ing form
could I not understudy? could you not understudy? could he not understudy? could we not understudy? could you not understudy? could they not understudy?	could I not be understudying? could you not be understudying? could he not be understudying? could we not be understudying? could you not be understudying? could they not be understudying?
Perfect	V-ing perfect
could I not have understudied? could you not have understudied? could he not have understudied? could we not have understudied? could you not have understudied? could they not have understudied?	could I not have been understudying? could you not have been understudying? could he not have been understudying? could we not have been understudying? could you not have been understudying? could they not have been understudying?