I could field-test you could field-test she could field-test we could field-test you could field-test they could field-test
V-ing form
I could be field-testing you could be field-testing she could be field-testing we could be field-testing you could be field-testing they could be field-testing
Perfect
I could have field-tested you could have field-tested she could have field-tested we could have field-tested you could have field-tested they could have field-tested
V-ing perfect
I could have been field-testing you could have been field-testing she could have been field-testing we could have been field-testing you could have been field-testing they could have been field-testing
Negation
Simple form
I couldn't field-test you couldn't field-test she couldn't field-test we couldn't field-test you couldn't field-test they couldn't field-test
V-ing form
I couldn't be field-testing you couldn't be field-testing she couldn't be field-testing we couldn't be field-testing you couldn't be field-testing they couldn't be field-testing
Perfect
I couldn't have field-tested you couldn't have field-tested she couldn't have field-tested we couldn't have field-tested you couldn't have field-tested they couldn't have field-tested
V-ing perfect
I couldn't have been field-testing you couldn't have been field-testing she couldn't have been field-testing we couldn't have been field-testing you couldn't have been field-testing they couldn't have been field-testing
Interrogative form
Simple form
could I field-test? could you field-test? could she field-test? could we field-test? could you field-test? could they field-test?
V-ing form
could I be field-testing? could you be field-testing? could she be field-testing? could we be field-testing? could you be field-testing? could they be field-testing?
Perfect
could I have field-tested? could you have field-tested? could she have field-tested? could we have field-tested? could you have field-tested? could they have field-tested?
V-ing perfect
could I have been field-testing? could you have been field-testing? could she have been field-testing? could we have been field-testing? could you have been field-testing? could they have been field-testing?
Interro-negative form
Simple form
couldn't I field-test? couldn't you field-test? couldn't she field-test? couldn't we field-test? couldn't you field-test? couldn't they field-test?
V-ing form
couldn't I be field-testing? couldn't you be field-testing? couldn't she be field-testing? couldn't we be field-testing? couldn't you be field-testing? couldn't they be field-testing?
Perfect
couldn't I have field-tested? couldn't you have field-tested? couldn't she have field-tested? couldn't we have field-tested? couldn't you have field-tested? couldn't they have field-tested?
V-ing perfect
couldn't I have been field-testing? couldn't you have been field-testing? couldn't she have been field-testing? couldn't we have been field-testing? couldn't you have been field-testing? couldn't they have been field-testing?