English verb conjugation
CAN RETAIN

Regular verb: retain - retained - retained

Affirmation

Simple form	V-ing form
I can retain you can retain he can retain we can retain you can retain they can retain	I can be retaining you can be retaining he can be retaining we can be retaining you can be retaining they can be retaining
Perfect	V-ing perfect
I can have retained you can have retained he can have retained we can have retained you can have retained they can have retained	I can have been retaining you can have been retaining he can have been retaining we can have been retaining you can have been retaining they can have been retaining

Negation

Simple form	V-ing form
I can't retain you can't retain he can't retain we can't retain you can't retain they can't retain	I can't be retaining you can't be retaining he can't be retaining we can't be retaining you can't be retaining they can't be retaining
Perfect	V-ing perfect
I can't have retained you can't have retained he can't have retained we can't have retained you can't have retained they can't have retained	I can't have been retaining you can't have been retaining he can't have been retaining we can't have been retaining you can't have been retaining they can't have been retaining

Interrogative form

Simple form	V-ing form
can I retain? can you retain? can he retain? can we retain? can you retain? can they retain?	can I be retaining? can you be retaining? can he be retaining? can we be retaining? can you be retaining? can they be retaining?
Perfect	V-ing perfect
can I have retained? can you have retained? can he have retained? can we have retained? can you have retained? can they have retained?	can I have been retaining? can you have been retaining? can he have been retaining? can we have been retaining? can you have been retaining? can they have been retaining?

Interro-negative form

Simple form	V-ing form
can't I retain? can't you retain? can't he retain? can't we retain? can't you retain? can't they retain?	can't I be retaining? can't you be retaining? can't he be retaining? can't we be retaining? can't you be retaining? can't they be retaining?
Perfect	V-ing perfect
can't I have retained? can't you have retained? can't he have retained? can't we have retained? can't you have retained? can't they have retained?	can't I have been retaining? can't you have been retaining? can't he have been retaining? can't we have been retaining? can't you have been retaining? can't they have been retaining?