I can retreat you can retreat she can retreat we can retreat you can retreat they can retreat
V-ing form
I can be retreating you can be retreating she can be retreating we can be retreating you can be retreating they can be retreating
Perfect
I can have retreated you can have retreated she 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 she can have been retreating we can have been retreating you can have been retreating they can have been retreating
Negation
Simple form
I cannot retreat you cannot retreat she cannot retreat we cannot retreat you cannot retreat they cannot retreat
V-ing form
I cannot be retreating you cannot be retreating she cannot be retreating we cannot be retreating you cannot be retreating they cannot be retreating
Perfect
I cannot have retreated you cannot have retreated she cannot have retreated we cannot have retreated you cannot have retreated they cannot have retreated
V-ing perfect
I cannot have been retreating you cannot have been retreating she cannot have been retreating we cannot have been retreating you cannot have been retreating they cannot have been retreating
Interrogative form
Simple form
can I retreat? can you retreat? can she retreat? can we retreat? can you retreat? can they retreat?
V-ing form
can I be retreating? can you be retreating? can she be retreating? can we be retreating? can you be retreating? can they be retreating?
Perfect
can I have retreated? can you have retreated? can she 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 she have been retreating? can we have been retreating? can you have been retreating? can they have been retreating?
Interro-negative form
Simple form
can I not retreat? can you not retreat? can she not retreat? can we not retreat? can you not retreat? can they not retreat?
V-ing form
can I not be retreating? can you not be retreating? can she not be retreating? can we not be retreating? can you not be retreating? can they not be retreating?
Perfect
can I not have retreated? can you not have retreated? can she not have retreated? can we not have retreated? can you not have retreated? can they not have retreated?
V-ing perfect
can I not have been retreating? can you not have been retreating? can she not have been retreating? can we not have been retreating? can you not have been retreating? can they not have been retreating?