could tranquillize
Regular verb: tranquillize - tranquillized- tranquillized

Affirmation 	
Simple form 	V-ing form 	Perfect 	V-ing perfect 	
I could tranquillize
you could tranquillize
he could tranquillize
we could tranquillize
you could tranquillize
they could tranquillize 	I could be tranquillizing
you could be tranquillizing
he could be tranquillizing
we could be tranquillizing
you could be tranquillizing
they could be tranquillizing	I could have tranquillized
you could have tranquillized
he could have tranquillized
we could have tranquillized
you could have tranquillized
they could have tranquillized	I could have been tranquillizing
you could have been tranquillizing
he could have been tranquillizing
we could have been tranquillizing
you could have been tranquillizing
they could have been tranquillizing	

Negation 	
Simple form 	V-ing form 	Perfect 	V-ing perfect 	
I couldn't tranquillize
you couldn't tranquillize
he couldn't tranquillize
we couldn't tranquillize
you couldn't tranquillize
they couldn't tranquillize 	I couldn't be tranquillizing
you couldn't be tranquillizing
he couldn't be tranquillizing
we couldn't be tranquillizing
you couldn't be tranquillizing
they couldn't be tranquillizing	I couldn't have tranquillized
you couldn't have tranquillized
he couldn't have tranquillized
we couldn't have tranquillized
you couldn't have tranquillized
they couldn't have tranquillized	I couldn't have been tranquillizing
you couldn't have been tranquillizing
he couldn't have been tranquillizing
we couldn't have been tranquillizing
you couldn't have been tranquillizing
they couldn't have been tranquillizing	

Interrogative form 	
Simple form 	V-ing form 	Perfect 	V-ing perfect 	
could I tranquillize?
could you tranquillize?
could he tranquillize?
could we tranquillize?
could you tranquillize?
could they tranquillize? 	could I be tranquillizing?
could you be tranquillizing?
could he be tranquillizing?
could we be tranquillizing?
could you be tranquillizing?
could they be tranquillizing? 	could I have tranquillized?
could you have tranquillized?
could he have tranquillized?
could we have tranquillized?
could you have tranquillized?
could they have tranquillized? 	could I have been tranquillizing?
could you have been tranquillizing?
could he have been tranquillizing?
could we have been tranquillizing?
could you have been tranquillizing?
could they have been tranquillizing? 	

Interro-negative form 	
Simple form 	V-ing form 	Perfect 	V-ing perfect 	
couldn't I tranquillize?
couldn't you tranquillize?
couldn't he tranquillize?
couldn't we tranquillize?
couldn't you tranquillize?
couldn't they tranquillize? 	couldn't I be tranquillizing?
couldn't you be tranquillizing?
couldn't he be tranquillizing?
couldn't we be tranquillizing?
couldn't you be tranquillizing?
couldn't they be tranquillizing? 	couldn't I have tranquillized?
couldn't you have tranquillized?
couldn't he have tranquillized?
couldn't we have tranquillized?
couldn't you have tranquillized?
couldn't they have tranquillized? 	couldn't I have been tranquillizing?
couldn't you have been tranquillizing?
couldn't he have been tranquillizing?
couldn't we have been tranquillizing?
couldn't you have been tranquillizing?
couldn't they have been tranquillizing?