I may crumble you may crumble he may crumble we may crumble you may crumble they may crumble
V-ing form
I may be crumbling you may be crumbling he may be crumbling we may be crumbling you may be crumbling they may be crumbling
Perfect
I may have crumbled you may have crumbled he may have crumbled we may have crumbled you may have crumbled they may have crumbled
V-ing perfect
I may have been crumbling you may have been crumbling he may have been crumbling we may have been crumbling you may have been crumbling they may have been crumbling
Negation
Simple form
I mayn't crumble you mayn't crumble he mayn't crumble we mayn't crumble you mayn't crumble they mayn't crumble
V-ing form
I mayn't be crumbling you mayn't be crumbling he mayn't be crumbling we mayn't be crumbling you mayn't be crumbling they mayn't be crumbling
Perfect
I mayn't have crumbled you mayn't have crumbled he mayn't have crumbled we mayn't have crumbled you mayn't have crumbled they mayn't have crumbled
V-ing perfect
I mayn't have been crumbling you mayn't have been crumbling he mayn't have been crumbling we mayn't have been crumbling you mayn't have been crumbling they mayn't have been crumbling
Interrogative form
Simple form
may I crumble? may you crumble? may he crumble? may we crumble? may you crumble? may they crumble?
V-ing form
may I be crumbling? may you be crumbling? may he be crumbling? may we be crumbling? may you be crumbling? may they be crumbling?
Perfect
may I have crumbled? may you have crumbled? may he have crumbled? may we have crumbled? may you have crumbled? may they have crumbled?
V-ing perfect
may I have been crumbling? may you have been crumbling? may he have been crumbling? may we have been crumbling? may you have been crumbling? may they have been crumbling?
Interro-negative form
Simple form
mayn't I crumble? mayn't you crumble? mayn't he crumble? mayn't we crumble? mayn't you crumble? mayn't they crumble?
V-ing form
mayn't I be crumbling? mayn't you be crumbling? mayn't he be crumbling? mayn't we be crumbling? mayn't you be crumbling? mayn't they be crumbling?
Perfect
mayn't I have crumbled? mayn't you have crumbled? mayn't he have crumbled? mayn't we have crumbled? mayn't you have crumbled? mayn't they have crumbled?
V-ing perfect
mayn't I have been crumbling? mayn't you have been crumbling? mayn't he have been crumbling? mayn't we have been crumbling? mayn't you have been crumbling? mayn't they have been crumbling?