I could gather you could gather he could gather we could gather you could gather they could gather
V-ing form
I could be gathering you could be gathering he could be gathering we could be gathering you could be gathering they could be gathering
Perfect
I could have gathered you could have gathered he could have gathered we could have gathered you could have gathered they could have gathered
V-ing perfect
I could have been gathering you could have been gathering he could have been gathering we could have been gathering you could have been gathering they could have been gathering
Negation
Simple form
I could not gather you could not gather he could not gather we could not gather you could not gather they could not gather
V-ing form
I could not be gathering you could not be gathering he could not be gathering we could not be gathering you could not be gathering they could not be gathering
Perfect
I could not have gathered you could not have gathered he could not have gathered we could not have gathered you could not have gathered they could not have gathered
V-ing perfect
I could not have been gathering you could not have been gathering he could not have been gathering we could not have been gathering you could not have been gathering they could not have been gathering
Interrogative form
Simple form
could I gather? could you gather? could he gather? could we gather? could you gather? could they gather?
V-ing form
could I be gathering? could you be gathering? could he be gathering? could we be gathering? could you be gathering? could they be gathering?
Perfect
could I have gathered? could you have gathered? could he have gathered? could we have gathered? could you have gathered? could they have gathered?
V-ing perfect
could I have been gathering? could you have been gathering? could he have been gathering? could we have been gathering? could you have been gathering? could they have been gathering?
Interro-negative form
Simple form
could I not gather? could you not gather? could he not gather? could we not gather? could you not gather? could they not gather?
V-ing form
could I not be gathering? could you not be gathering? could he not be gathering? could we not be gathering? could you not be gathering? could they not be gathering?
Perfect
could I not have gathered? could you not have gathered? could he not have gathered? could we not have gathered? could you not have gathered? could they not have gathered?
V-ing perfect
could I not have been gathering? could you not have been gathering? could he not have been gathering? could we not have been gathering? could you not have been gathering? could they not have been gathering?