English verb conjugation
COULD THINK

Irregular verb: think - thought - thought

Affirmation

Simple form	V-ing form
I could think you could think he could think we could think you could think they could think	I could be thinking you could be thinking he could be thinking we could be thinking you could be thinking they could be thinking
Perfect	V-ing perfect
I could have thought you could have thought he could have thought we could have thought you could have thought they could have thought	I could have been thinking you could have been thinking he could have been thinking we could have been thinking you could have been thinking they could have been thinking

Negation

Simple form	V-ing form
I could not think you could not think he could not think we could not think you could not think they could not think	I could not be thinking you could not be thinking he could not be thinking we could not be thinking you could not be thinking they could not be thinking
Perfect	V-ing perfect
I could not have thought you could not have thought he could not have thought we could not have thought you could not have thought they could not have thought	I could not have been thinking you could not have been thinking he could not have been thinking we could not have been thinking you could not have been thinking they could not have been thinking

Interrogative form

Simple form	V-ing form
could I think? could you think? could he think? could we think? could you think? could they think?	could I be thinking? could you be thinking? could he be thinking? could we be thinking? could you be thinking? could they be thinking?
Perfect	V-ing perfect
could I have thought? could you have thought? could he have thought? could we have thought? could you have thought? could they have thought?	could I have been thinking? could you have been thinking? could he have been thinking? could we have been thinking? could you have been thinking? could they have been thinking?

Interro-negative form

Simple form	V-ing form
could I not think? could you not think? could he not think? could we not think? could you not think? could they not think?	could I not be thinking? could you not be thinking? could he not be thinking? could we not be thinking? could you not be thinking? could they not be thinking?
Perfect	V-ing perfect
could I not have thought? could you not have thought? could he not have thought? could we not have thought? could you not have thought? could they not have thought?	could I not have been thinking? could you not have been thinking? could he not have been thinking? could we not have been thinking? could you not have been thinking? could they not have been thinking?