could clatter
Regular verb: clatter - clattered- clattered

Affirmation 	
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I could clatter
you could clatter
he could clatter
we could clatter
you could clatter
they could clatter 	I could be clattering
you could be clattering
he could be clattering
we could be clattering
you could be clattering
they could be clattering	I could have clattered
you could have clattered
he could have clattered
we could have clattered
you could have clattered
they could have clattered	I could have been clattering
you could have been clattering
he could have been clattering
we could have been clattering
you could have been clattering
they could have been clattering	

Negation 	
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I could not clatter
you could not clatter
he could not clatter
we could not clatter
you could not clatter
they could not clatter 	I could not be clattering
you could not be clattering
he could not be clattering
we could not be clattering
you could not be clattering
they could not be clattering	I could not have clattered
you could not have clattered
he could not have clattered
we could not have clattered
you could not have clattered
they could not have clattered	I could not have been clattering
you could not have been clattering
he could not have been clattering
we could not have been clattering
you could not have been clattering
they could not have been clattering	

Interrogative form 	
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could I clatter?
could you clatter?
could he clatter?
could we clatter?
could you clatter?
could they clatter? 	could I be clattering?
could you be clattering?
could he be clattering?
could we be clattering?
could you be clattering?
could they be clattering? 	could I have clattered?
could you have clattered?
could he have clattered?
could we have clattered?
could you have clattered?
could they have clattered? 	could I have been clattering?
could you have been clattering?
could he have been clattering?
could we have been clattering?
could you have been clattering?
could they have been clattering? 	

Interro-negative form 	
Simple form 	V-ing form 	Perfect 	V-ing perfect 	
could I not clatter?
could you not clatter?
could he not clatter?
could we not clatter?
could you not clatter?
could they not clatter? 	could I not be clattering?
could you not be clattering?
could he not be clattering?
could we not be clattering?
could you not be clattering?
could they not be clattering? 	could I not have clattered?
could you not have clattered?
could he not have clattered?
could we not have clattered?
could you not have clattered?
could they not have clattered? 	could I not have been clattering?
could you not have been clattering?
could he not have been clattering?
could we not have been clattering?
could you not have been clattering?
could they not have been clattering?