could decongest
Regular verb: decongest - decongested- decongested

Affirmation 	
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I could decongest
you could decongest
he could decongest
we could decongest
you could decongest
they could decongest 	I could be decongesting
you could be decongesting
he could be decongesting
we could be decongesting
you could be decongesting
they could be decongesting	I could have decongested
you could have decongested
he could have decongested
we could have decongested
you could have decongested
they could have decongested	I could have been decongesting
you could have been decongesting
he could have been decongesting
we could have been decongesting
you could have been decongesting
they could have been decongesting	

Negation 	
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I couldn't decongest
you couldn't decongest
he couldn't decongest
we couldn't decongest
you couldn't decongest
they couldn't decongest 	I couldn't be decongesting
you couldn't be decongesting
he couldn't be decongesting
we couldn't be decongesting
you couldn't be decongesting
they couldn't be decongesting	I couldn't have decongested
you couldn't have decongested
he couldn't have decongested
we couldn't have decongested
you couldn't have decongested
they couldn't have decongested	I couldn't have been decongesting
you couldn't have been decongesting
he couldn't have been decongesting
we couldn't have been decongesting
you couldn't have been decongesting
they couldn't have been decongesting	

Interrogative form 	
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could I decongest?
could you decongest?
could he decongest?
could we decongest?
could you decongest?
could they decongest? 	could I be decongesting?
could you be decongesting?
could he be decongesting?
could we be decongesting?
could you be decongesting?
could they be decongesting? 	could I have decongested?
could you have decongested?
could he have decongested?
could we have decongested?
could you have decongested?
could they have decongested? 	could I have been decongesting?
could you have been decongesting?
could he have been decongesting?
could we have been decongesting?
could you have been decongesting?
could they have been decongesting? 	

Interro-negative form 	
Simple form 	V-ing form 	Perfect 	V-ing perfect 	
couldn't I decongest?
couldn't you decongest?
couldn't he decongest?
couldn't we decongest?
couldn't you decongest?
couldn't they decongest? 	couldn't I be decongesting?
couldn't you be decongesting?
couldn't he be decongesting?
couldn't we be decongesting?
couldn't you be decongesting?
couldn't they be decongesting? 	couldn't I have decongested?
couldn't you have decongested?
couldn't he have decongested?
couldn't we have decongested?
couldn't you have decongested?
couldn't they have decongested? 	couldn't I have been decongesting?
couldn't you have been decongesting?
couldn't he have been decongesting?
couldn't we have been decongesting?
couldn't you have been decongesting?
couldn't they have been decongesting?