English verb conjugation
COULD REPLY

Regular verb: reply - replied - replied

Affirmation

Simple form	V-ing form
I could reply you could reply she could reply we could reply you could reply they could reply	I could be replying you could be replying she could be replying we could be replying you could be replying they could be replying
Perfect	V-ing perfect
I could have replied you could have replied she could have replied we could have replied you could have replied they could have replied	I could have been replying you could have been replying she could have been replying we could have been replying you could have been replying they could have been replying

Negation

Simple form	V-ing form
I couldn't reply you couldn't reply she couldn't reply we couldn't reply you couldn't reply they couldn't reply	I couldn't be replying you couldn't be replying she couldn't be replying we couldn't be replying you couldn't be replying they couldn't be replying
Perfect	V-ing perfect
I couldn't have replied you couldn't have replied she couldn't have replied we couldn't have replied you couldn't have replied they couldn't have replied	I couldn't have been replying you couldn't have been replying she couldn't have been replying we couldn't have been replying you couldn't have been replying they couldn't have been replying

Interrogative form

Simple form	V-ing form
could I reply? could you reply? could she reply? could we reply? could you reply? could they reply?	could I be replying? could you be replying? could she be replying? could we be replying? could you be replying? could they be replying?
Perfect	V-ing perfect
could I have replied? could you have replied? could she have replied? could we have replied? could you have replied? could they have replied?	could I have been replying? could you have been replying? could she have been replying? could we have been replying? could you have been replying? could they have been replying?

Interro-negative form

Simple form	V-ing form
couldn't I reply? couldn't you reply? couldn't she reply? couldn't we reply? couldn't you reply? couldn't they reply?	couldn't I be replying? couldn't you be replying? couldn't she be replying? couldn't we be replying? couldn't you be replying? couldn't they be replying?
Perfect	V-ing perfect
couldn't I have replied? couldn't you have replied? couldn't she have replied? couldn't we have replied? couldn't you have replied? couldn't they have replied?	couldn't I have been replying? couldn't you have been replying? couldn't she have been replying? couldn't we have been replying? couldn't you have been replying? couldn't they have been replying?