could diminish
Regular verb: diminish - diminished- diminished

Affirmation 	
Simple form 	V-ing form 	Perfect 	V-ing perfect 	
I could diminish
you could diminish
she could diminish
we could diminish
you could diminish
they could diminish 	I could be diminishing
you could be diminishing
she could be diminishing
we could be diminishing
you could be diminishing
they could be diminishing	I could have diminished
you could have diminished
she could have diminished
we could have diminished
you could have diminished
they could have diminished	I could have been diminishing
you could have been diminishing
she could have been diminishing
we could have been diminishing
you could have been diminishing
they could have been diminishing	

Negation 	
Simple form 	V-ing form 	Perfect 	V-ing perfect 	
I couldn't diminish
you couldn't diminish
she couldn't diminish
we couldn't diminish
you couldn't diminish
they couldn't diminish 	I couldn't be diminishing
you couldn't be diminishing
she couldn't be diminishing
we couldn't be diminishing
you couldn't be diminishing
they couldn't be diminishing	I couldn't have diminished
you couldn't have diminished
she couldn't have diminished
we couldn't have diminished
you couldn't have diminished
they couldn't have diminished	I couldn't have been diminishing
you couldn't have been diminishing
she couldn't have been diminishing
we couldn't have been diminishing
you couldn't have been diminishing
they couldn't have been diminishing	

Interrogative form 	
Simple form 	V-ing form 	Perfect 	V-ing perfect 	
could I diminish?
could you diminish?
could she diminish?
could we diminish?
could you diminish?
could they diminish? 	could I be diminishing?
could you be diminishing?
could she be diminishing?
could we be diminishing?
could you be diminishing?
could they be diminishing? 	could I have diminished?
could you have diminished?
could she have diminished?
could we have diminished?
could you have diminished?
could they have diminished? 	could I have been diminishing?
could you have been diminishing?
could she have been diminishing?
could we have been diminishing?
could you have been diminishing?
could they have been diminishing? 	

Interro-negative form 	
Simple form 	V-ing form 	Perfect 	V-ing perfect 	
couldn't I diminish?
couldn't you diminish?
couldn't she diminish?
couldn't we diminish?
couldn't you diminish?
couldn't they diminish? 	couldn't I be diminishing?
couldn't you be diminishing?
couldn't she be diminishing?
couldn't we be diminishing?
couldn't you be diminishing?
couldn't they be diminishing? 	couldn't I have diminished?
couldn't you have diminished?
couldn't she have diminished?
couldn't we have diminished?
couldn't you have diminished?
couldn't they have diminished? 	couldn't I have been diminishing?
couldn't you have been diminishing?
couldn't she have been diminishing?
couldn't we have been diminishing?
couldn't you have been diminishing?
couldn't they have been diminishing?