I can trade you can trade he can trade we can trade you can trade they can trade
V-ing form
I can be trading you can be trading he can be trading we can be trading you can be trading they can be trading
Perfect
I can have traded you can have traded he can have traded we can have traded you can have traded they can have traded
V-ing perfect
I can have been trading you can have been trading he can have been trading we can have been trading you can have been trading they can have been trading
Negation
Simple form
I can't trade you can't trade he can't trade we can't trade you can't trade they can't trade
V-ing form
I can't be trading you can't be trading he can't be trading we can't be trading you can't be trading they can't be trading
Perfect
I can't have traded you can't have traded he can't have traded we can't have traded you can't have traded they can't have traded
V-ing perfect
I can't have been trading you can't have been trading he can't have been trading we can't have been trading you can't have been trading they can't have been trading
Interrogative form
Simple form
can I trade? can you trade? can he trade? can we trade? can you trade? can they trade?
V-ing form
can I be trading? can you be trading? can he be trading? can we be trading? can you be trading? can they be trading?
Perfect
can I have traded? can you have traded? can he have traded? can we have traded? can you have traded? can they have traded?
V-ing perfect
can I have been trading? can you have been trading? can he have been trading? can we have been trading? can you have been trading? can they have been trading?
Interro-negative form
Simple form
can't I trade? can't you trade? can't he trade? can't we trade? can't you trade? can't they trade?
V-ing form
can't I be trading? can't you be trading? can't he be trading? can't we be trading? can't you be trading? can't they be trading?
Perfect
can't I have traded? can't you have traded? can't he have traded? can't we have traded? can't you have traded? can't they have traded?
V-ing perfect
can't I have been trading? can't you have been trading? can't he have been trading? can't we have been trading? can't you have been trading? can't they have been trading?