could peak
Regular verb: peak - peaked- peaked

Affirmation 	
Simple form 	V-ing form 	Perfect 	V-ing perfect 	
I could peak
you could peak
he could peak
we could peak
you could peak
they could peak 	I could be peaking
you could be peaking
he could be peaking
we could be peaking
you could be peaking
they could be peaking	I could have peaked
you could have peaked
he could have peaked
we could have peaked
you could have peaked
they could have peaked	I could have been peaking
you could have been peaking
he could have been peaking
we could have been peaking
you could have been peaking
they could have been peaking	

Negation 	
Simple form 	V-ing form 	Perfect 	V-ing perfect 	
I couldn't peak
you couldn't peak
he couldn't peak
we couldn't peak
you couldn't peak
they couldn't peak 	I couldn't be peaking
you couldn't be peaking
he couldn't be peaking
we couldn't be peaking
you couldn't be peaking
they couldn't be peaking	I couldn't have peaked
you couldn't have peaked
he couldn't have peaked
we couldn't have peaked
you couldn't have peaked
they couldn't have peaked	I couldn't have been peaking
you couldn't have been peaking
he couldn't have been peaking
we couldn't have been peaking
you couldn't have been peaking
they couldn't have been peaking	

Interrogative form 	
Simple form 	V-ing form 	Perfect 	V-ing perfect 	
could I peak?
could you peak?
could he peak?
could we peak?
could you peak?
could they peak? 	could I be peaking?
could you be peaking?
could he be peaking?
could we be peaking?
could you be peaking?
could they be peaking? 	could I have peaked?
could you have peaked?
could he have peaked?
could we have peaked?
could you have peaked?
could they have peaked? 	could I have been peaking?
could you have been peaking?
could he have been peaking?
could we have been peaking?
could you have been peaking?
could they have been peaking? 	

Interro-negative form 	
Simple form 	V-ing form 	Perfect 	V-ing perfect 	
couldn't I peak?
couldn't you peak?
couldn't he peak?
couldn't we peak?
couldn't you peak?
couldn't they peak? 	couldn't I be peaking?
couldn't you be peaking?
couldn't he be peaking?
couldn't we be peaking?
couldn't you be peaking?
couldn't they be peaking? 	couldn't I have peaked?
couldn't you have peaked?
couldn't he have peaked?
couldn't we have peaked?
couldn't you have peaked?
couldn't they have peaked? 	couldn't I have been peaking?
couldn't you have been peaking?
couldn't he have been peaking?
couldn't we have been peaking?
couldn't you have been peaking?
couldn't they have been peaking?