I can double you can double he can double we can double you can double they can double
V-ing form
I can be doubling you can be doubling he can be doubling we can be doubling you can be doubling they can be doubling
Perfect
I can have doubled you can have doubled he can have doubled we can have doubled you can have doubled they can have doubled
V-ing perfect
I can have been doubling you can have been doubling he can have been doubling we can have been doubling you can have been doubling they can have been doubling
Negation
Simple form
I can't double you can't double he can't double we can't double you can't double they can't double
V-ing form
I can't be doubling you can't be doubling he can't be doubling we can't be doubling you can't be doubling they can't be doubling
Perfect
I can't have doubled you can't have doubled he can't have doubled we can't have doubled you can't have doubled they can't have doubled
V-ing perfect
I can't have been doubling you can't have been doubling he can't have been doubling we can't have been doubling you can't have been doubling they can't have been doubling
Interrogative form
Simple form
can I double? can you double? can he double? can we double? can you double? can they double?
V-ing form
can I be doubling? can you be doubling? can he be doubling? can we be doubling? can you be doubling? can they be doubling?
Perfect
can I have doubled? can you have doubled? can he have doubled? can we have doubled? can you have doubled? can they have doubled?
V-ing perfect
can I have been doubling? can you have been doubling? can he have been doubling? can we have been doubling? can you have been doubling? can they have been doubling?
Interro-negative form
Simple form
can't I double? can't you double? can't he double? can't we double? can't you double? can't they double?
V-ing form
can't I be doubling? can't you be doubling? can't he be doubling? can't we be doubling? can't you be doubling? can't they be doubling?
Perfect
can't I have doubled? can't you have doubled? can't he have doubled? can't we have doubled? can't you have doubled? can't they have doubled?
V-ing perfect
can't I have been doubling? can't you have been doubling? can't he have been doubling? can't we have been doubling? can't you have been doubling? can't they have been doubling?