I may contribute you may contribute he may contribute we may contribute you may contribute they may contribute
V-ing form
I may be contributing you may be contributing he may be contributing we may be contributing you may be contributing they may be contributing
Perfect
I may have contributed you may have contributed he may have contributed we may have contributed you may have contributed they may have contributed
V-ing perfect
I may have been contributing you may have been contributing he may have been contributing we may have been contributing you may have been contributing they may have been contributing
Negation
Simple form
I may not contribute you may not contribute he may not contribute we may not contribute you may not contribute they may not contribute
V-ing form
I may not be contributing you may not be contributing he may not be contributing we may not be contributing you may not be contributing they may not be contributing
Perfect
I may not have contributed you may not have contributed he may not have contributed we may not have contributed you may not have contributed they may not have contributed
V-ing perfect
I may not have been contributing you may not have been contributing he may not have been contributing we may not have been contributing you may not have been contributing they may not have been contributing
Interrogative form
Simple form
may I contribute? may you contribute? may he contribute? may we contribute? may you contribute? may they contribute?
V-ing form
may I be contributing? may you be contributing? may he be contributing? may we be contributing? may you be contributing? may they be contributing?
Perfect
may I have contributed? may you have contributed? may he have contributed? may we have contributed? may you have contributed? may they have contributed?
V-ing perfect
may I have been contributing? may you have been contributing? may he have been contributing? may we have been contributing? may you have been contributing? may they have been contributing?
Interro-negative form
Simple form
may I not contribute? may you not contribute? may he not contribute? may we not contribute? may you not contribute? may they not contribute?
V-ing form
may I not be contributing? may you not be contributing? may he not be contributing? may we not be contributing? may you not be contributing? may they not be contributing?
Perfect
may I not have contributed? may you not have contributed? may he not have contributed? may we not have contributed? may you not have contributed? may they not have contributed?
V-ing perfect
may I not have been contributing? may you not have been contributing? may he not have been contributing? may we not have been contributing? may you not have been contributing? may they not have been contributing?