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 mayn't contribute you mayn't contribute he mayn't contribute we mayn't contribute you mayn't contribute they mayn't contribute
V-ing form
I mayn't be contributing you mayn't be contributing he mayn't be contributing we mayn't be contributing you mayn't be contributing they mayn't be contributing
Perfect
I mayn't have contributed you mayn't have contributed he mayn't have contributed we mayn't have contributed you mayn't have contributed they mayn't have contributed
V-ing perfect
I mayn't have been contributing you mayn't have been contributing he mayn't have been contributing we mayn't have been contributing you mayn't have been contributing they mayn't 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
mayn't I contribute? mayn't you contribute? mayn't he contribute? mayn't we contribute? mayn't you contribute? mayn't they contribute?
V-ing form
mayn't I be contributing? mayn't you be contributing? mayn't he be contributing? mayn't we be contributing? mayn't you be contributing? mayn't they be contributing?
Perfect
mayn't I have contributed? mayn't you have contributed? mayn't he have contributed? mayn't we have contributed? mayn't you have contributed? mayn't they have contributed?
V-ing perfect
mayn't I have been contributing? mayn't you have been contributing? mayn't he have been contributing? mayn't we have been contributing? mayn't you have been contributing? mayn't they have been contributing?