English verb conjugation
COULD UNDERSTUDY

Regular verb: understudy - understudied - understudied

Affirmation

Simple form	V-ing form
I could understudy you could understudy she could understudy we could understudy you could understudy they could understudy	I could be understudying you could be understudying she 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 she 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 she 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 couldn't understudy you couldn't understudy she couldn't understudy we couldn't understudy you couldn't understudy they couldn't understudy	I couldn't be understudying you couldn't be understudying she couldn't be understudying we couldn't be understudying you couldn't be understudying they couldn't be understudying
Perfect	V-ing perfect
I couldn't have understudied you couldn't have understudied she couldn't have understudied we couldn't have understudied you couldn't have understudied they couldn't have understudied	I couldn't have been understudying you couldn't have been understudying she couldn't have been understudying we couldn't have been understudying you couldn't have been understudying they couldn't have been understudying

Interrogative form

Simple form	V-ing form
could I understudy? could you understudy? could she understudy? could we understudy? could you understudy? could they understudy?	could I be understudying? could you be understudying? could she 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 she 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 she 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
couldn't I understudy? couldn't you understudy? couldn't she understudy? couldn't we understudy? couldn't you understudy? couldn't they understudy?	couldn't I be understudying? couldn't you be understudying? couldn't she be understudying? couldn't we be understudying? couldn't you be understudying? couldn't they be understudying?
Perfect	V-ing perfect
couldn't I have understudied? couldn't you have understudied? couldn't she have understudied? couldn't we have understudied? couldn't you have understudied? couldn't they have understudied?	couldn't I have been understudying? couldn't you have been understudying? couldn't she have been understudying? couldn't we have been understudying? couldn't you have been understudying? couldn't they have been understudying?