I can retreat you can retreat he can retreat we can retreat you can retreat they can retreat
V-ing form
I can be retreating you can be retreating he can be retreating we can be retreating you can be retreating they can be retreating
Perfect
I can have retreated you can have retreated he can have retreated we can have retreated you can have retreated they can have retreated
V-ing perfect
I can have been retreating you can have been retreating he can have been retreating we can have been retreating you can have been retreating they can have been retreating
Negation
Simple form
I can't retreat you can't retreat he can't retreat we can't retreat you can't retreat they can't retreat
V-ing form
I can't be retreating you can't be retreating he can't be retreating we can't be retreating you can't be retreating they can't be retreating
Perfect
I can't have retreated you can't have retreated he can't have retreated we can't have retreated you can't have retreated they can't have retreated
V-ing perfect
I can't have been retreating you can't have been retreating he can't have been retreating we can't have been retreating you can't have been retreating they can't have been retreating
Interrogative form
Simple form
can I retreat? can you retreat? can he retreat? can we retreat? can you retreat? can they retreat?
V-ing form
can I be retreating? can you be retreating? can he be retreating? can we be retreating? can you be retreating? can they be retreating?
Perfect
can I have retreated? can you have retreated? can he have retreated? can we have retreated? can you have retreated? can they have retreated?
V-ing perfect
can I have been retreating? can you have been retreating? can he have been retreating? can we have been retreating? can you have been retreating? can they have been retreating?
Interro-negative form
Simple form
can't I retreat? can't you retreat? can't he retreat? can't we retreat? can't you retreat? can't they retreat?
V-ing form
can't I be retreating? can't you be retreating? can't he be retreating? can't we be retreating? can't you be retreating? can't they be retreating?
Perfect
can't I have retreated? can't you have retreated? can't he have retreated? can't we have retreated? can't you have retreated? can't they have retreated?
V-ing perfect
can't I have been retreating? can't you have been retreating? can't he have been retreating? can't we have been retreating? can't you have been retreating? can't they have been retreating?