I can square you can square he can square we can square you can square they can square
V-ing form
I can be squaring you can be squaring he can be squaring we can be squaring you can be squaring they can be squaring
Perfect
I can have squared you can have squared he can have squared we can have squared you can have squared they can have squared
V-ing perfect
I can have been squaring you can have been squaring he can have been squaring we can have been squaring you can have been squaring they can have been squaring
Negation
Simple form
I cannot square you cannot square he cannot square we cannot square you cannot square they cannot square
V-ing form
I cannot be squaring you cannot be squaring he cannot be squaring we cannot be squaring you cannot be squaring they cannot be squaring
Perfect
I cannot have squared you cannot have squared he cannot have squared we cannot have squared you cannot have squared they cannot have squared
V-ing perfect
I cannot have been squaring you cannot have been squaring he cannot have been squaring we cannot have been squaring you cannot have been squaring they cannot have been squaring
Interrogative form
Simple form
can I square? can you square? can he square? can we square? can you square? can they square?
V-ing form
can I be squaring? can you be squaring? can he be squaring? can we be squaring? can you be squaring? can they be squaring?
Perfect
can I have squared? can you have squared? can he have squared? can we have squared? can you have squared? can they have squared?
V-ing perfect
can I have been squaring? can you have been squaring? can he have been squaring? can we have been squaring? can you have been squaring? can they have been squaring?
Interro-negative form
Simple form
can I not square? can you not square? can he not square? can we not square? can you not square? can they not square?
V-ing form
can I not be squaring? can you not be squaring? can he not be squaring? can we not be squaring? can you not be squaring? can they not be squaring?
Perfect
can I not have squared? can you not have squared? can he not have squared? can we not have squared? can you not have squared? can they not have squared?
V-ing perfect
can I not have been squaring? can you not have been squaring? can he not have been squaring? can we not have been squaring? can you not have been squaring? can they not have been squaring?