I could materialize you could materialize he could materialize we could materialize you could materialize they could materialize
V-ing form
I could be materializing you could be materializing he could be materializing we could be materializing you could be materializing they could be materializing
Perfect
I could have materialized you could have materialized he could have materialized we could have materialized you could have materialized they could have materialized
V-ing perfect
I could have been materializing you could have been materializing he could have been materializing we could have been materializing you could have been materializing they could have been materializing
Negation
Simple form
I couldn't materialize you couldn't materialize he couldn't materialize we couldn't materialize you couldn't materialize they couldn't materialize
V-ing form
I couldn't be materializing you couldn't be materializing he couldn't be materializing we couldn't be materializing you couldn't be materializing they couldn't be materializing
Perfect
I couldn't have materialized you couldn't have materialized he couldn't have materialized we couldn't have materialized you couldn't have materialized they couldn't have materialized
V-ing perfect
I couldn't have been materializing you couldn't have been materializing he couldn't have been materializing we couldn't have been materializing you couldn't have been materializing they couldn't have been materializing
Interrogative form
Simple form
could I materialize? could you materialize? could he materialize? could we materialize? could you materialize? could they materialize?
V-ing form
could I be materializing? could you be materializing? could he be materializing? could we be materializing? could you be materializing? could they be materializing?
Perfect
could I have materialized? could you have materialized? could he have materialized? could we have materialized? could you have materialized? could they have materialized?
V-ing perfect
could I have been materializing? could you have been materializing? could he have been materializing? could we have been materializing? could you have been materializing? could they have been materializing?
Interro-negative form
Simple form
couldn't I materialize? couldn't you materialize? couldn't he materialize? couldn't we materialize? couldn't you materialize? couldn't they materialize?
V-ing form
couldn't I be materializing? couldn't you be materializing? couldn't he be materializing? couldn't we be materializing? couldn't you be materializing? couldn't they be materializing?
Perfect
couldn't I have materialized? couldn't you have materialized? couldn't he have materialized? couldn't we have materialized? couldn't you have materialized? couldn't they have materialized?
V-ing perfect
couldn't I have been materializing? couldn't you have been materializing? couldn't he have been materializing? couldn't we have been materializing? couldn't you have been materializing? couldn't they have been materializing?