English verb conjugation
COULD SQUARE

Regular verb: square - squared - squared

Affirmation

Simple form	V-ing form
I could square you could square he could square we could square you could square they could square	I could be squaring you could be squaring he could be squaring we could be squaring you could be squaring they could be squaring
Perfect	V-ing perfect
I could have squared you could have squared he could have squared we could have squared you could have squared they could have squared	I could have been squaring you could have been squaring he could have been squaring we could have been squaring you could have been squaring they could have been squaring

Negation

Simple form	V-ing form
I couldn't square you couldn't square he couldn't square we couldn't square you couldn't square they couldn't square	I couldn't be squaring you couldn't be squaring he couldn't be squaring we couldn't be squaring you couldn't be squaring they couldn't be squaring
Perfect	V-ing perfect
I couldn't have squared you couldn't have squared he couldn't have squared we couldn't have squared you couldn't have squared they couldn't have squared	I couldn't have been squaring you couldn't have been squaring he couldn't have been squaring we couldn't have been squaring you couldn't have been squaring they couldn't have been squaring

Interrogative form

Simple form	V-ing form
could I square? could you square? could he square? could we square? could you square? could they square?	could I be squaring? could you be squaring? could he be squaring? could we be squaring? could you be squaring? could they be squaring?
Perfect	V-ing perfect
could I have squared? could you have squared? could he have squared? could we have squared? could you have squared? could they have squared?	could I have been squaring? could you have been squaring? could he have been squaring? could we have been squaring? could you have been squaring? could they have been squaring?

Interro-negative form

Simple form	V-ing form
couldn't I square? couldn't you square? couldn't he square? couldn't we square? couldn't you square? couldn't they square?	couldn't I be squaring? couldn't you be squaring? couldn't he be squaring? couldn't we be squaring? couldn't you be squaring? couldn't they be squaring?
Perfect	V-ing perfect
couldn't I have squared? couldn't you have squared? couldn't he have squared? couldn't we have squared? couldn't you have squared? couldn't they have squared?	couldn't I have been squaring? couldn't you have been squaring? couldn't he have been squaring? couldn't we have been squaring? couldn't you have been squaring? couldn't they have been squaring?