could clunk
Regular verb: clunk - clunked- clunked

Affirmation 	
Simple form 	V-ing form 	Perfect 	V-ing perfect 	
I could clunk
you could clunk
he could clunk
we could clunk
you could clunk
they could clunk 	I could be clunking
you could be clunking
he could be clunking
we could be clunking
you could be clunking
they could be clunking	I could have clunked
you could have clunked
he could have clunked
we could have clunked
you could have clunked
they could have clunked	I could have been clunking
you could have been clunking
he could have been clunking
we could have been clunking
you could have been clunking
they could have been clunking	

Negation 	
Simple form 	V-ing form 	Perfect 	V-ing perfect 	
I couldn't clunk
you couldn't clunk
he couldn't clunk
we couldn't clunk
you couldn't clunk
they couldn't clunk 	I couldn't be clunking
you couldn't be clunking
he couldn't be clunking
we couldn't be clunking
you couldn't be clunking
they couldn't be clunking	I couldn't have clunked
you couldn't have clunked
he couldn't have clunked
we couldn't have clunked
you couldn't have clunked
they couldn't have clunked	I couldn't have been clunking
you couldn't have been clunking
he couldn't have been clunking
we couldn't have been clunking
you couldn't have been clunking
they couldn't have been clunking	

Interrogative form 	
Simple form 	V-ing form 	Perfect 	V-ing perfect 	
could I clunk?
could you clunk?
could he clunk?
could we clunk?
could you clunk?
could they clunk? 	could I be clunking?
could you be clunking?
could he be clunking?
could we be clunking?
could you be clunking?
could they be clunking? 	could I have clunked?
could you have clunked?
could he have clunked?
could we have clunked?
could you have clunked?
could they have clunked? 	could I have been clunking?
could you have been clunking?
could he have been clunking?
could we have been clunking?
could you have been clunking?
could they have been clunking? 	

Interro-negative form 	
Simple form 	V-ing form 	Perfect 	V-ing perfect 	
couldn't I clunk?
couldn't you clunk?
couldn't he clunk?
couldn't we clunk?
couldn't you clunk?
couldn't they clunk? 	couldn't I be clunking?
couldn't you be clunking?
couldn't he be clunking?
couldn't we be clunking?
couldn't you be clunking?
couldn't they be clunking? 	couldn't I have clunked?
couldn't you have clunked?
couldn't he have clunked?
couldn't we have clunked?
couldn't you have clunked?
couldn't they have clunked? 	couldn't I have been clunking?
couldn't you have been clunking?
couldn't he have been clunking?
couldn't we have been clunking?
couldn't you have been clunking?
couldn't they have been clunking?