I could approximate you could approximate he could approximate we could approximate you could approximate they could approximate
V-ing form
I could be approximating you could be approximating he could be approximating we could be approximating you could be approximating they could be approximating
Perfect
I could have approximated you could have approximated he could have approximated we could have approximated you could have approximated they could have approximated
V-ing perfect
I could have been approximating you could have been approximating he could have been approximating we could have been approximating you could have been approximating they could have been approximating
Negation
Simple form
I could not approximate you could not approximate he could not approximate we could not approximate you could not approximate they could not approximate
V-ing form
I could not be approximating you could not be approximating he could not be approximating we could not be approximating you could not be approximating they could not be approximating
Perfect
I could not have approximated you could not have approximated he could not have approximated we could not have approximated you could not have approximated they could not have approximated
V-ing perfect
I could not have been approximating you could not have been approximating he could not have been approximating we could not have been approximating you could not have been approximating they could not have been approximating
Interrogative form
Simple form
could I approximate? could you approximate? could he approximate? could we approximate? could you approximate? could they approximate?
V-ing form
could I be approximating? could you be approximating? could he be approximating? could we be approximating? could you be approximating? could they be approximating?
Perfect
could I have approximated? could you have approximated? could he have approximated? could we have approximated? could you have approximated? could they have approximated?
V-ing perfect
could I have been approximating? could you have been approximating? could he have been approximating? could we have been approximating? could you have been approximating? could they have been approximating?
Interro-negative form
Simple form
could I not approximate? could you not approximate? could he not approximate? could we not approximate? could you not approximate? could they not approximate?
V-ing form
could I not be approximating? could you not be approximating? could he not be approximating? could we not be approximating? could you not be approximating? could they not be approximating?
Perfect
could I not have approximated? could you not have approximated? could he not have approximated? could we not have approximated? could you not have approximated? could they not have approximated?
V-ing perfect
could I not have been approximating? could you not have been approximating? could he not have been approximating? could we not have been approximating? could you not have been approximating? could they not have been approximating?