English verb conjugation
COULD TEST

Regular verb: test - tested - tested

Affirmation

Simple form	V-ing form
I could test you could test she could test we could test you could test they could test	I could be testing you could be testing she could be testing we could be testing you could be testing they could be testing
Perfect	V-ing perfect
I could have tested you could have tested she could have tested we could have tested you could have tested they could have tested	I could have been testing you could have been testing she could have been testing we could have been testing you could have been testing they could have been testing

Negation

Simple form	V-ing form
I could not test you could not test she could not test we could not test you could not test they could not test	I could not be testing you could not be testing she could not be testing we could not be testing you could not be testing they could not be testing
Perfect	V-ing perfect
I could not have tested you could not have tested she could not have tested we could not have tested you could not have tested they could not have tested	I could not have been testing you could not have been testing she could not have been testing we could not have been testing you could not have been testing they could not have been testing

Interrogative form

Simple form	V-ing form
could I test? could you test? could she test? could we test? could you test? could they test?	could I be testing? could you be testing? could she be testing? could we be testing? could you be testing? could they be testing?
Perfect	V-ing perfect
could I have tested? could you have tested? could she have tested? could we have tested? could you have tested? could they have tested?	could I have been testing? could you have been testing? could she have been testing? could we have been testing? could you have been testing? could they have been testing?

Interro-negative form

Simple form	V-ing form
could I not test? could you not test? could she not test? could we not test? could you not test? could they not test?	could I not be testing? could you not be testing? could she not be testing? could we not be testing? could you not be testing? could they not be testing?
Perfect	V-ing perfect
could I not have tested? could you not have tested? could she not have tested? could we not have tested? could you not have tested? could they not have tested?	could I not have been testing? could you not have been testing? could she not have been testing? could we not have been testing? could you not have been testing? could they not have been testing?