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 couldn't test you couldn't test she couldn't test we couldn't test you couldn't test they couldn't test	I couldn't be testing you couldn't be testing she couldn't be testing we couldn't be testing you couldn't be testing they couldn't be testing
Perfect	V-ing perfect
I couldn't have tested you couldn't have tested she couldn't have tested we couldn't have tested you couldn't have tested they couldn't have tested	I couldn't have been testing you couldn't have been testing she couldn't have been testing we couldn't have been testing you couldn't have been testing they couldn't 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
couldn't I test? couldn't you test? couldn't she test? couldn't we test? couldn't you test? couldn't they test?	couldn't I be testing? couldn't you be testing? couldn't she be testing? couldn't we be testing? couldn't you be testing? couldn't they be testing?
Perfect	V-ing perfect
couldn't I have tested? couldn't you have tested? couldn't she have tested? couldn't we have tested? couldn't you have tested? couldn't they have tested?	couldn't I have been testing? couldn't you have been testing? couldn't she have been testing? couldn't we have been testing? couldn't you have been testing? couldn't they have been testing?