English verb conjugation
COULD CLERK

Regular verb: clerk - clerked - clerked

Affirmation

Simple form	V-ing form
I could clerk you could clerk he could clerk we could clerk you could clerk they could clerk	I could be clerking you could be clerking he could be clerking we could be clerking you could be clerking they could be clerking
Perfect	V-ing perfect
I could have clerked you could have clerked he could have clerked we could have clerked you could have clerked they could have clerked	I could have been clerking you could have been clerking he could have been clerking we could have been clerking you could have been clerking they could have been clerking

Negation

Simple form	V-ing form
I couldn't clerk you couldn't clerk he couldn't clerk we couldn't clerk you couldn't clerk they couldn't clerk	I couldn't be clerking you couldn't be clerking he couldn't be clerking we couldn't be clerking you couldn't be clerking they couldn't be clerking
Perfect	V-ing perfect
I couldn't have clerked you couldn't have clerked he couldn't have clerked we couldn't have clerked you couldn't have clerked they couldn't have clerked	I couldn't have been clerking you couldn't have been clerking he couldn't have been clerking we couldn't have been clerking you couldn't have been clerking they couldn't have been clerking

Interrogative form

Simple form	V-ing form
could I clerk? could you clerk? could he clerk? could we clerk? could you clerk? could they clerk?	could I be clerking? could you be clerking? could he be clerking? could we be clerking? could you be clerking? could they be clerking?
Perfect	V-ing perfect
could I have clerked? could you have clerked? could he have clerked? could we have clerked? could you have clerked? could they have clerked?	could I have been clerking? could you have been clerking? could he have been clerking? could we have been clerking? could you have been clerking? could they have been clerking?

Interro-negative form

Simple form	V-ing form
couldn't I clerk? couldn't you clerk? couldn't he clerk? couldn't we clerk? couldn't you clerk? couldn't they clerk?	couldn't I be clerking? couldn't you be clerking? couldn't he be clerking? couldn't we be clerking? couldn't you be clerking? couldn't they be clerking?
Perfect	V-ing perfect
couldn't I have clerked? couldn't you have clerked? couldn't he have clerked? couldn't we have clerked? couldn't you have clerked? couldn't they have clerked?	couldn't I have been clerking? couldn't you have been clerking? couldn't he have been clerking? couldn't we have been clerking? couldn't you have been clerking? couldn't they have been clerking?