could sightsee
Regular verb: sightsee - sightseed- sightseed

Affirmation 	
Simple form 	V-ing form 	Perfect 	V-ing perfect 	
I could sightsee
you could sightsee
she could sightsee
we could sightsee
you could sightsee
they could sightsee 	I could be sightseeing
you could be sightseeing
she could be sightseeing
we could be sightseeing
you could be sightseeing
they could be sightseeing	I could have sightseed
you could have sightseed
she could have sightseed
we could have sightseed
you could have sightseed
they could have sightseed	I could have been sightseeing
you could have been sightseeing
she could have been sightseeing
we could have been sightseeing
you could have been sightseeing
they could have been sightseeing	

Negation 	
Simple form 	V-ing form 	Perfect 	V-ing perfect 	
I couldn't sightsee
you couldn't sightsee
she couldn't sightsee
we couldn't sightsee
you couldn't sightsee
they couldn't sightsee 	I couldn't be sightseeing
you couldn't be sightseeing
she couldn't be sightseeing
we couldn't be sightseeing
you couldn't be sightseeing
they couldn't be sightseeing	I couldn't have sightseed
you couldn't have sightseed
she couldn't have sightseed
we couldn't have sightseed
you couldn't have sightseed
they couldn't have sightseed	I couldn't have been sightseeing
you couldn't have been sightseeing
she couldn't have been sightseeing
we couldn't have been sightseeing
you couldn't have been sightseeing
they couldn't have been sightseeing	

Interrogative form 	
Simple form 	V-ing form 	Perfect 	V-ing perfect 	
could I sightsee?
could you sightsee?
could she sightsee?
could we sightsee?
could you sightsee?
could they sightsee? 	could I be sightseeing?
could you be sightseeing?
could she be sightseeing?
could we be sightseeing?
could you be sightseeing?
could they be sightseeing? 	could I have sightseed?
could you have sightseed?
could she have sightseed?
could we have sightseed?
could you have sightseed?
could they have sightseed? 	could I have been sightseeing?
could you have been sightseeing?
could she have been sightseeing?
could we have been sightseeing?
could you have been sightseeing?
could they have been sightseeing? 	

Interro-negative form 	
Simple form 	V-ing form 	Perfect 	V-ing perfect 	
couldn't I sightsee?
couldn't you sightsee?
couldn't she sightsee?
couldn't we sightsee?
couldn't you sightsee?
couldn't they sightsee? 	couldn't I be sightseeing?
couldn't you be sightseeing?
couldn't she be sightseeing?
couldn't we be sightseeing?
couldn't you be sightseeing?
couldn't they be sightseeing? 	couldn't I have sightseed?
couldn't you have sightseed?
couldn't she have sightseed?
couldn't we have sightseed?
couldn't you have sightseed?
couldn't they have sightseed? 	couldn't I have been sightseeing?
couldn't you have been sightseeing?
couldn't she have been sightseeing?
couldn't we have been sightseeing?
couldn't you have been sightseeing?
couldn't they have been sightseeing?