I can contend you can contend he can contend we can contend you can contend they can contend
V-ing form
I can be contending you can be contending he can be contending we can be contending you can be contending they can be contending
Perfect
I can have contended you can have contended he can have contended we can have contended you can have contended they can have contended
V-ing perfect
I can have been contending you can have been contending he can have been contending we can have been contending you can have been contending they can have been contending
Negation
Simple form
I can't contend you can't contend he can't contend we can't contend you can't contend they can't contend
V-ing form
I can't be contending you can't be contending he can't be contending we can't be contending you can't be contending they can't be contending
Perfect
I can't have contended you can't have contended he can't have contended we can't have contended you can't have contended they can't have contended
V-ing perfect
I can't have been contending you can't have been contending he can't have been contending we can't have been contending you can't have been contending they can't have been contending
Interrogative form
Simple form
can I contend? can you contend? can he contend? can we contend? can you contend? can they contend?
V-ing form
can I be contending? can you be contending? can he be contending? can we be contending? can you be contending? can they be contending?
Perfect
can I have contended? can you have contended? can he have contended? can we have contended? can you have contended? can they have contended?
V-ing perfect
can I have been contending? can you have been contending? can he have been contending? can we have been contending? can you have been contending? can they have been contending?
Interro-negative form
Simple form
can't I contend? can't you contend? can't he contend? can't we contend? can't you contend? can't they contend?
V-ing form
can't I be contending? can't you be contending? can't he be contending? can't we be contending? can't you be contending? can't they be contending?
Perfect
can't I have contended? can't you have contended? can't he have contended? can't we have contended? can't you have contended? can't they have contended?
V-ing perfect
can't I have been contending? can't you have been contending? can't he have been contending? can't we have been contending? can't you have been contending? can't they have been contending?