could endanger
Regular verb: endanger - endangered- endangered

Affirmation 	
Simple form 	V-ing form 	Perfect 	V-ing perfect 	
I could endanger
you could endanger
he could endanger
we could endanger
you could endanger
they could endanger 	I could be endangering
you could be endangering
he could be endangering
we could be endangering
you could be endangering
they could be endangering	I could have endangered
you could have endangered
he could have endangered
we could have endangered
you could have endangered
they could have endangered	I could have been endangering
you could have been endangering
he could have been endangering
we could have been endangering
you could have been endangering
they could have been endangering	

Negation 	
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I couldn't endanger
you couldn't endanger
he couldn't endanger
we couldn't endanger
you couldn't endanger
they couldn't endanger 	I couldn't be endangering
you couldn't be endangering
he couldn't be endangering
we couldn't be endangering
you couldn't be endangering
they couldn't be endangering	I couldn't have endangered
you couldn't have endangered
he couldn't have endangered
we couldn't have endangered
you couldn't have endangered
they couldn't have endangered	I couldn't have been endangering
you couldn't have been endangering
he couldn't have been endangering
we couldn't have been endangering
you couldn't have been endangering
they couldn't have been endangering	

Interrogative form 	
Simple form 	V-ing form 	Perfect 	V-ing perfect 	
could I endanger?
could you endanger?
could he endanger?
could we endanger?
could you endanger?
could they endanger? 	could I be endangering?
could you be endangering?
could he be endangering?
could we be endangering?
could you be endangering?
could they be endangering? 	could I have endangered?
could you have endangered?
could he have endangered?
could we have endangered?
could you have endangered?
could they have endangered? 	could I have been endangering?
could you have been endangering?
could he have been endangering?
could we have been endangering?
could you have been endangering?
could they have been endangering? 	

Interro-negative form 	
Simple form 	V-ing form 	Perfect 	V-ing perfect 	
couldn't I endanger?
couldn't you endanger?
couldn't he endanger?
couldn't we endanger?
couldn't you endanger?
couldn't they endanger? 	couldn't I be endangering?
couldn't you be endangering?
couldn't he be endangering?
couldn't we be endangering?
couldn't you be endangering?
couldn't they be endangering? 	couldn't I have endangered?
couldn't you have endangered?
couldn't he have endangered?
couldn't we have endangered?
couldn't you have endangered?
couldn't they have endangered? 	couldn't I have been endangering?
couldn't you have been endangering?
couldn't he have been endangering?
couldn't we have been endangering?
couldn't you have been endangering?
couldn't they have been endangering?