English verb conjugation
COULD MATURE

Regular verb: mature - matured - matured

Affirmation

Simple form	V-ing form
I could mature you could mature he could mature we could mature you could mature they could mature	I could be maturing you could be maturing he could be maturing we could be maturing you could be maturing they could be maturing
Perfect	V-ing perfect
I could have matured you could have matured he could have matured we could have matured you could have matured they could have matured	I could have been maturing you could have been maturing he could have been maturing we could have been maturing you could have been maturing they could have been maturing

Negation

Simple form	V-ing form
I could not mature you could not mature he could not mature we could not mature you could not mature they could not mature	I could not be maturing you could not be maturing he could not be maturing we could not be maturing you could not be maturing they could not be maturing
Perfect	V-ing perfect
I could not have matured you could not have matured he could not have matured we could not have matured you could not have matured they could not have matured	I could not have been maturing you could not have been maturing he could not have been maturing we could not have been maturing you could not have been maturing they could not have been maturing

Interrogative form

Simple form	V-ing form
could I mature? could you mature? could he mature? could we mature? could you mature? could they mature?	could I be maturing? could you be maturing? could he be maturing? could we be maturing? could you be maturing? could they be maturing?
Perfect	V-ing perfect
could I have matured? could you have matured? could he have matured? could we have matured? could you have matured? could they have matured?	could I have been maturing? could you have been maturing? could he have been maturing? could we have been maturing? could you have been maturing? could they have been maturing?

Interro-negative form

Simple form	V-ing form
could I not mature? could you not mature? could he not mature? could we not mature? could you not mature? could they not mature?	could I not be maturing? could you not be maturing? could he not be maturing? could we not be maturing? could you not be maturing? could they not be maturing?
Perfect	V-ing perfect
could I not have matured? could you not have matured? could he not have matured? could we not have matured? could you not have matured? could they not have matured?	could I not have been maturing? could you not have been maturing? could he not have been maturing? could we not have been maturing? could you not have been maturing? could they not have been maturing?