I can grade you can grade he can grade we can grade you can grade they can grade
Forma con V-ing
I can be grading you can be grading he can be grading we can be grading you can be grading they can be grading
Perfecto
I can have graded you can have graded he can have graded we can have graded you can have graded they can have graded
Perfecto con V-ing
I can have been grading you can have been grading he can have been grading we can have been grading you can have been grading they can have been grading
Negación
Forma simple
I can't grade you can't grade he can't grade we can't grade you can't grade they can't grade
Forma con V-ing
I can't be grading you can't be grading he can't be grading we can't be grading you can't be grading they can't be grading
Perfecto
I can't have graded you can't have graded he can't have graded we can't have graded you can't have graded they can't have graded
Perfecto con V-ing
I can't have been grading you can't have been grading he can't have been grading we can't have been grading you can't have been grading they can't have been grading
Forma interrogativa
Forma simple
can I grade? can you grade? can he grade? can we grade? can you grade? can they grade?
Forma con V-ing
can I be grading? can you be grading? can he be grading? can we be grading? can you be grading? can they be grading?
Perfecto
can I have graded? can you have graded? can he have graded? can we have graded? can you have graded? can they have graded?
Perfecto con V-ing
can I have been grading? can you have been grading? can he have been grading? can we have been grading? can you have been grading? can they have been grading?
Forma interro-negativa
Forma simple
can't I grade? can't you grade? can't he grade? can't we grade? can't you grade? can't they grade?
Forma con V-ing
can't I be grading? can't you be grading? can't he be grading? can't we be grading? can't you be grading? can't they be grading?
Perfecto
can't I have graded? can't you have graded? can't he have graded? can't we have graded? can't you have graded? can't they have graded?
Perfecto con V-ing
can't I have been grading? can't you have been grading? can't he have been grading? can't we have been grading? can't you have been grading? can't they have been grading?