could alert
Regular verb: alert - alerted- alerted

Affirmation 	
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I could alert
you could alert
he could alert
we could alert
you could alert
they could alert 	I could be alerting
you could be alerting
he could be alerting
we could be alerting
you could be alerting
they could be alerting	I could have alerted
you could have alerted
he could have alerted
we could have alerted
you could have alerted
they could have alerted	I could have been alerting
you could have been alerting
he could have been alerting
we could have been alerting
you could have been alerting
they could have been alerting	

Negation 	
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I could not alert
you could not alert
he could not alert
we could not alert
you could not alert
they could not alert 	I could not be alerting
you could not be alerting
he could not be alerting
we could not be alerting
you could not be alerting
they could not be alerting	I could not have alerted
you could not have alerted
he could not have alerted
we could not have alerted
you could not have alerted
they could not have alerted	I could not have been alerting
you could not have been alerting
he could not have been alerting
we could not have been alerting
you could not have been alerting
they could not have been alerting	

Interrogative form 	
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could I alert?
could you alert?
could he alert?
could we alert?
could you alert?
could they alert? 	could I be alerting?
could you be alerting?
could he be alerting?
could we be alerting?
could you be alerting?
could they be alerting? 	could I have alerted?
could you have alerted?
could he have alerted?
could we have alerted?
could you have alerted?
could they have alerted? 	could I have been alerting?
could you have been alerting?
could he have been alerting?
could we have been alerting?
could you have been alerting?
could they have been alerting? 	

Interro-negative form 	
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could I not alert?
could you not alert?
could he not alert?
could we not alert?
could you not alert?
could they not alert? 	could I not be alerting?
could you not be alerting?
could he not be alerting?
could we not be alerting?
could you not be alerting?
could they not be alerting? 	could I not have alerted?
could you not have alerted?
could he not have alerted?
could we not have alerted?
could you not have alerted?
could they not have alerted? 	could I not have been alerting?
could you not have been alerting?
could he not have been alerting?
could we not have been alerting?
could you not have been alerting?
could they not have been alerting?