English verb conjugation
COULD PROTOTYPE

Regular verb: prototype - prototyped - prototyped

Affirmation

Simple form	V-ing form
I could prototype you could prototype she could prototype we could prototype you could prototype they could prototype	I could be prototyping you could be prototyping she could be prototyping we could be prototyping you could be prototyping they could be prototyping
Perfect	V-ing perfect
I could have prototyped you could have prototyped she could have prototyped we could have prototyped you could have prototyped they could have prototyped	I could have been prototyping you could have been prototyping she could have been prototyping we could have been prototyping you could have been prototyping they could have been prototyping

Negation

Simple form	V-ing form
I couldn't prototype you couldn't prototype she couldn't prototype we couldn't prototype you couldn't prototype they couldn't prototype	I couldn't be prototyping you couldn't be prototyping she couldn't be prototyping we couldn't be prototyping you couldn't be prototyping they couldn't be prototyping
Perfect	V-ing perfect
I couldn't have prototyped you couldn't have prototyped she couldn't have prototyped we couldn't have prototyped you couldn't have prototyped they couldn't have prototyped	I couldn't have been prototyping you couldn't have been prototyping she couldn't have been prototyping we couldn't have been prototyping you couldn't have been prototyping they couldn't have been prototyping

Interrogative form

Simple form	V-ing form
could I prototype? could you prototype? could she prototype? could we prototype? could you prototype? could they prototype?	could I be prototyping? could you be prototyping? could she be prototyping? could we be prototyping? could you be prototyping? could they be prototyping?
Perfect	V-ing perfect
could I have prototyped? could you have prototyped? could she have prototyped? could we have prototyped? could you have prototyped? could they have prototyped?	could I have been prototyping? could you have been prototyping? could she have been prototyping? could we have been prototyping? could you have been prototyping? could they have been prototyping?

Interro-negative form

Simple form	V-ing form
couldn't I prototype? couldn't you prototype? couldn't she prototype? couldn't we prototype? couldn't you prototype? couldn't they prototype?	couldn't I be prototyping? couldn't you be prototyping? couldn't she be prototyping? couldn't we be prototyping? couldn't you be prototyping? couldn't they be prototyping?
Perfect	V-ing perfect
couldn't I have prototyped? couldn't you have prototyped? couldn't she have prototyped? couldn't we have prototyped? couldn't you have prototyped? couldn't they have prototyped?	couldn't I have been prototyping? couldn't you have been prototyping? couldn't she have been prototyping? couldn't we have been prototyping? couldn't you have been prototyping? couldn't they have been prototyping?