English verb conjugation
CAN CLACK

Regular verb: clack - clacked - clacked

Affirmation

Simple form	V-ing form
I can clack you can clack she can clack we can clack you can clack they can clack	I can be clacking you can be clacking she can be clacking we can be clacking you can be clacking they can be clacking
Perfect	V-ing perfect
I can have clacked you can have clacked she can have clacked we can have clacked you can have clacked they can have clacked	I can have been clacking you can have been clacking she can have been clacking we can have been clacking you can have been clacking they can have been clacking

Negation

Simple form	V-ing form
I can't clack you can't clack she can't clack we can't clack you can't clack they can't clack	I can't be clacking you can't be clacking she can't be clacking we can't be clacking you can't be clacking they can't be clacking
Perfect	V-ing perfect
I can't have clacked you can't have clacked she can't have clacked we can't have clacked you can't have clacked they can't have clacked	I can't have been clacking you can't have been clacking she can't have been clacking we can't have been clacking you can't have been clacking they can't have been clacking

Interrogative form

Simple form	V-ing form
can I clack? can you clack? can she clack? can we clack? can you clack? can they clack?	can I be clacking? can you be clacking? can she be clacking? can we be clacking? can you be clacking? can they be clacking?
Perfect	V-ing perfect
can I have clacked? can you have clacked? can she have clacked? can we have clacked? can you have clacked? can they have clacked?	can I have been clacking? can you have been clacking? can she have been clacking? can we have been clacking? can you have been clacking? can they have been clacking?

Interro-negative form

Simple form	V-ing form
can't I clack? can't you clack? can't she clack? can't we clack? can't you clack? can't they clack?	can't I be clacking? can't you be clacking? can't she be clacking? can't we be clacking? can't you be clacking? can't they be clacking?
Perfect	V-ing perfect
can't I have clacked? can't you have clacked? can't she have clacked? can't we have clacked? can't you have clacked? can't they have clacked?	can't I have been clacking? can't you have been clacking? can't she have been clacking? can't we have been clacking? can't you have been clacking? can't they have been clacking?