could fathom
Regular verb: fathom - fathomed- fathomed

Affirmation 	
Simple form 	V-ing form 	Perfect 	V-ing perfect 	
I could fathom
you could fathom
she could fathom
we could fathom
you could fathom
they could fathom 	I could be fathoming
you could be fathoming
she could be fathoming
we could be fathoming
you could be fathoming
they could be fathoming	I could have fathomed
you could have fathomed
she could have fathomed
we could have fathomed
you could have fathomed
they could have fathomed	I could have been fathoming
you could have been fathoming
she could have been fathoming
we could have been fathoming
you could have been fathoming
they could have been fathoming	

Negation 	
Simple form 	V-ing form 	Perfect 	V-ing perfect 	
I couldn't fathom
you couldn't fathom
she couldn't fathom
we couldn't fathom
you couldn't fathom
they couldn't fathom 	I couldn't be fathoming
you couldn't be fathoming
she couldn't be fathoming
we couldn't be fathoming
you couldn't be fathoming
they couldn't be fathoming	I couldn't have fathomed
you couldn't have fathomed
she couldn't have fathomed
we couldn't have fathomed
you couldn't have fathomed
they couldn't have fathomed	I couldn't have been fathoming
you couldn't have been fathoming
she couldn't have been fathoming
we couldn't have been fathoming
you couldn't have been fathoming
they couldn't have been fathoming	

Interrogative form 	
Simple form 	V-ing form 	Perfect 	V-ing perfect 	
could I fathom?
could you fathom?
could she fathom?
could we fathom?
could you fathom?
could they fathom? 	could I be fathoming?
could you be fathoming?
could she be fathoming?
could we be fathoming?
could you be fathoming?
could they be fathoming? 	could I have fathomed?
could you have fathomed?
could she have fathomed?
could we have fathomed?
could you have fathomed?
could they have fathomed? 	could I have been fathoming?
could you have been fathoming?
could she have been fathoming?
could we have been fathoming?
could you have been fathoming?
could they have been fathoming? 	

Interro-negative form 	
Simple form 	V-ing form 	Perfect 	V-ing perfect 	
couldn't I fathom?
couldn't you fathom?
couldn't she fathom?
couldn't we fathom?
couldn't you fathom?
couldn't they fathom? 	couldn't I be fathoming?
couldn't you be fathoming?
couldn't she be fathoming?
couldn't we be fathoming?
couldn't you be fathoming?
couldn't they be fathoming? 	couldn't I have fathomed?
couldn't you have fathomed?
couldn't she have fathomed?
couldn't we have fathomed?
couldn't you have fathomed?
couldn't they have fathomed? 	couldn't I have been fathoming?
couldn't you have been fathoming?
couldn't she have been fathoming?
couldn't we have been fathoming?
couldn't you have been fathoming?
couldn't they have been fathoming?