could advertise
Regular verb: advertise - advertised- advertised

Affirmation 	
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I could advertise
you could advertise
he could advertise
we could advertise
you could advertise
they could advertise 	I could be advertising
you could be advertising
he could be advertising
we could be advertising
you could be advertising
they could be advertising	I could have advertised
you could have advertised
he could have advertised
we could have advertised
you could have advertised
they could have advertised	I could have been advertising
you could have been advertising
he could have been advertising
we could have been advertising
you could have been advertising
they could have been advertising	

Negation 	
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I couldn't advertise
you couldn't advertise
he couldn't advertise
we couldn't advertise
you couldn't advertise
they couldn't advertise 	I couldn't be advertising
you couldn't be advertising
he couldn't be advertising
we couldn't be advertising
you couldn't be advertising
they couldn't be advertising	I couldn't have advertised
you couldn't have advertised
he couldn't have advertised
we couldn't have advertised
you couldn't have advertised
they couldn't have advertised	I couldn't have been advertising
you couldn't have been advertising
he couldn't have been advertising
we couldn't have been advertising
you couldn't have been advertising
they couldn't have been advertising	

Interrogative form 	
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could I advertise?
could you advertise?
could he advertise?
could we advertise?
could you advertise?
could they advertise? 	could I be advertising?
could you be advertising?
could he be advertising?
could we be advertising?
could you be advertising?
could they be advertising? 	could I have advertised?
could you have advertised?
could he have advertised?
could we have advertised?
could you have advertised?
could they have advertised? 	could I have been advertising?
could you have been advertising?
could he have been advertising?
could we have been advertising?
could you have been advertising?
could they have been advertising? 	

Interro-negative form 	
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couldn't I advertise?
couldn't you advertise?
couldn't he advertise?
couldn't we advertise?
couldn't you advertise?
couldn't they advertise? 	couldn't I be advertising?
couldn't you be advertising?
couldn't he be advertising?
couldn't we be advertising?
couldn't you be advertising?
couldn't they be advertising? 	couldn't I have advertised?
couldn't you have advertised?
couldn't he have advertised?
couldn't we have advertised?
couldn't you have advertised?
couldn't they have advertised? 	couldn't I have been advertising?
couldn't you have been advertising?
couldn't he have been advertising?
couldn't we have been advertising?
couldn't you have been advertising?
couldn't they have been advertising?