I could express you could express she could express we could express you could express they could express
V-ing form
I could be expressing you could be expressing she could be expressing we could be expressing you could be expressing they could be expressing
Perfect
I could have expressed you could have expressed she could have expressed we could have expressed you could have expressed they could have expressed
V-ing perfect
I could have been expressing you could have been expressing she could have been expressing we could have been expressing you could have been expressing they could have been expressing
Negation
Simple form
I could not express you could not express she could not express we could not express you could not express they could not express
V-ing form
I could not be expressing you could not be expressing she could not be expressing we could not be expressing you could not be expressing they could not be expressing
Perfect
I could not have expressed you could not have expressed she could not have expressed we could not have expressed you could not have expressed they could not have expressed
V-ing perfect
I could not have been expressing you could not have been expressing she could not have been expressing we could not have been expressing you could not have been expressing they could not have been expressing
Interrogative form
Simple form
could I express? could you express? could she express? could we express? could you express? could they express?
V-ing form
could I be expressing? could you be expressing? could she be expressing? could we be expressing? could you be expressing? could they be expressing?
Perfect
could I have expressed? could you have expressed? could she have expressed? could we have expressed? could you have expressed? could they have expressed?
V-ing perfect
could I have been expressing? could you have been expressing? could she have been expressing? could we have been expressing? could you have been expressing? could they have been expressing?
Interro-negative form
Simple form
could I not express? could you not express? could she not express? could we not express? could you not express? could they not express?
V-ing form
could I not be expressing? could you not be expressing? could she not be expressing? could we not be expressing? could you not be expressing? could they not be expressing?
Perfect
could I not have expressed? could you not have expressed? could she not have expressed? could we not have expressed? could you not have expressed? could they not have expressed?
V-ing perfect
could I not have been expressing? could you not have been expressing? could she not have been expressing? could we not have been expressing? could you not have been expressing? could they not have been expressing?