English verb conjugation
CAN ROOF

Regular verb: roof - roofed - roofed

Affirmation

Simple form	V-ing form
I can roof you can roof he can roof we can roof you can roof they can roof	I can be roofing you can be roofing he can be roofing we can be roofing you can be roofing they can be roofing
Perfect	V-ing perfect
I can have roofed you can have roofed he can have roofed we can have roofed you can have roofed they can have roofed	I can have been roofing you can have been roofing he can have been roofing we can have been roofing you can have been roofing they can have been roofing

Negation

Simple form	V-ing form
I can't roof you can't roof he can't roof we can't roof you can't roof they can't roof	I can't be roofing you can't be roofing he can't be roofing we can't be roofing you can't be roofing they can't be roofing
Perfect	V-ing perfect
I can't have roofed you can't have roofed he can't have roofed we can't have roofed you can't have roofed they can't have roofed	I can't have been roofing you can't have been roofing he can't have been roofing we can't have been roofing you can't have been roofing they can't have been roofing

Interrogative form

Simple form	V-ing form
can I roof? can you roof? can he roof? can we roof? can you roof? can they roof?	can I be roofing? can you be roofing? can he be roofing? can we be roofing? can you be roofing? can they be roofing?
Perfect	V-ing perfect
can I have roofed? can you have roofed? can he have roofed? can we have roofed? can you have roofed? can they have roofed?	can I have been roofing? can you have been roofing? can he have been roofing? can we have been roofing? can you have been roofing? can they have been roofing?

Interro-negative form

Simple form	V-ing form
can't I roof? can't you roof? can't he roof? can't we roof? can't you roof? can't they roof?	can't I be roofing? can't you be roofing? can't he be roofing? can't we be roofing? can't you be roofing? can't they be roofing?
Perfect	V-ing perfect
can't I have roofed? can't you have roofed? can't he have roofed? can't we have roofed? can't you have roofed? can't they have roofed?	can't I have been roofing? can't you have been roofing? can't he have been roofing? can't we have been roofing? can't you have been roofing? can't they have been roofing?