I could bumble you could bumble she could bumble we could bumble you could bumble they could bumble
V-ing form
I could be bumbling you could be bumbling she could be bumbling we could be bumbling you could be bumbling they could be bumbling
Perfect
I could have bumbled you could have bumbled she could have bumbled we could have bumbled you could have bumbled they could have bumbled
V-ing perfect
I could have been bumbling you could have been bumbling she could have been bumbling we could have been bumbling you could have been bumbling they could have been bumbling
Negation
Simple form
I couldn't bumble you couldn't bumble she couldn't bumble we couldn't bumble you couldn't bumble they couldn't bumble
V-ing form
I couldn't be bumbling you couldn't be bumbling she couldn't be bumbling we couldn't be bumbling you couldn't be bumbling they couldn't be bumbling
Perfect
I couldn't have bumbled you couldn't have bumbled she couldn't have bumbled we couldn't have bumbled you couldn't have bumbled they couldn't have bumbled
V-ing perfect
I couldn't have been bumbling you couldn't have been bumbling she couldn't have been bumbling we couldn't have been bumbling you couldn't have been bumbling they couldn't have been bumbling
Interrogative form
Simple form
could I bumble? could you bumble? could she bumble? could we bumble? could you bumble? could they bumble?
V-ing form
could I be bumbling? could you be bumbling? could she be bumbling? could we be bumbling? could you be bumbling? could they be bumbling?
Perfect
could I have bumbled? could you have bumbled? could she have bumbled? could we have bumbled? could you have bumbled? could they have bumbled?
V-ing perfect
could I have been bumbling? could you have been bumbling? could she have been bumbling? could we have been bumbling? could you have been bumbling? could they have been bumbling?
Interro-negative form
Simple form
couldn't I bumble? couldn't you bumble? couldn't she bumble? couldn't we bumble? couldn't you bumble? couldn't they bumble?
V-ing form
couldn't I be bumbling? couldn't you be bumbling? couldn't she be bumbling? couldn't we be bumbling? couldn't you be bumbling? couldn't they be bumbling?
Perfect
couldn't I have bumbled? couldn't you have bumbled? couldn't she have bumbled? couldn't we have bumbled? couldn't you have bumbled? couldn't they have bumbled?
V-ing perfect
couldn't I have been bumbling? couldn't you have been bumbling? couldn't she have been bumbling? couldn't we have been bumbling? couldn't you have been bumbling? couldn't they have been bumbling?