could research
Verbe régulier : research - researched- researched
Traduction française : faire des recherches sur - faire des recherches ou de la recherche 

Affirmation 	
Forme simple 	Forme en V-ing 	Perfect 	Perfect en V-ing 	
I could research
you could research
he could research
we could research
you could research
they could research 	I could be researching
you could be researching
he could be researching
we could be researching
you could be researching
they could be researching	I could have researched
you could have researched
he could have researched
we could have researched
you could have researched
they could have researched	I could have been researching
you could have been researching
he could have been researching
we could have been researching
you could have been researching
they could have been researching	

Négation 	
Forme simple 	Forme en V-ing 	Perfect 	Perfect en V-ing 	
I couldn't research
you couldn't research
he couldn't research
we couldn't research
you couldn't research
they couldn't research 	I couldn't be researching
you couldn't be researching
he couldn't be researching
we couldn't be researching
you couldn't be researching
they couldn't be researching	I couldn't have researched
you couldn't have researched
he couldn't have researched
we couldn't have researched
you couldn't have researched
they couldn't have researched	I couldn't have been researching
you couldn't have been researching
he couldn't have been researching
we couldn't have been researching
you couldn't have been researching
they couldn't have been researching	

Forme interrogative 	
Forme simple 	Forme en V-ing 	Perfect 	Perfect en V-ing 	
could I research?
could you research?
could he research?
could we research?
could you research?
could they research? 	could I be researching?
could you be researching?
could he be researching?
could we be researching?
could you be researching?
could they be researching? 	could I have researched?
could you have researched?
could he have researched?
could we have researched?
could you have researched?
could they have researched? 	could I have been researching?
could you have been researching?
could he have been researching?
could we have been researching?
could you have been researching?
could they have been researching? 	

Forme interro-négative 	
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couldn't I research?
couldn't you research?
couldn't he research?
couldn't we research?
couldn't you research?
couldn't they research? 	couldn't I be researching?
couldn't you be researching?
couldn't he be researching?
couldn't we be researching?
couldn't you be researching?
couldn't they be researching? 	couldn't I have researched?
couldn't you have researched?
couldn't he have researched?
couldn't we have researched?
couldn't you have researched?
couldn't they have researched? 	couldn't I have been researching?
couldn't you have been researching?
couldn't he have been researching?
couldn't we have been researching?
couldn't you have been researching?
couldn't they have been researching?