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