I can string you can string he can string we can string you can string they can string
V-ing form
I can be stringing you can be stringing he can be stringing we can be stringing you can be stringing they can be stringing
Perfect
I can have strung you can have strung he can have strung we can have strung you can have strung they can have strung
V-ing perfect
I can have been stringing you can have been stringing he can have been stringing we can have been stringing you can have been stringing they can have been stringing
Negation
Simple form
I can't string you can't string he can't string we can't string you can't string they can't string
V-ing form
I can't be stringing you can't be stringing he can't be stringing we can't be stringing you can't be stringing they can't be stringing
Perfect
I can't have strung you can't have strung he can't have strung we can't have strung you can't have strung they can't have strung
V-ing perfect
I can't have been stringing you can't have been stringing he can't have been stringing we can't have been stringing you can't have been stringing they can't have been stringing
Interrogative form
Simple form
can I string? can you string? can he string? can we string? can you string? can they string?
V-ing form
can I be stringing? can you be stringing? can he be stringing? can we be stringing? can you be stringing? can they be stringing?
Perfect
can I have strung? can you have strung? can he have strung? can we have strung? can you have strung? can they have strung?
V-ing perfect
can I have been stringing? can you have been stringing? can he have been stringing? can we have been stringing? can you have been stringing? can they have been stringing?
Interro-negative form
Simple form
can't I string? can't you string? can't he string? can't we string? can't you string? can't they string?
V-ing form
can't I be stringing? can't you be stringing? can't he be stringing? can't we be stringing? can't you be stringing? can't they be stringing?
Perfect
can't I have strung? can't you have strung? can't he have strung? can't we have strung? can't you have strung? can't they have strung?
V-ing perfect
can't I have been stringing? can't you have been stringing? can't he have been stringing? can't we have been stringing? can't you have been stringing? can't they have been stringing?