I can welter you can welter he can welter we can welter you can welter they can welter
V-ing form
I can be weltering you can be weltering he can be weltering we can be weltering you can be weltering they can be weltering
Perfect
I can have weltered you can have weltered he can have weltered we can have weltered you can have weltered they can have weltered
V-ing perfect
I can have been weltering you can have been weltering he can have been weltering we can have been weltering you can have been weltering they can have been weltering
Negation
Simple form
I can't welter you can't welter he can't welter we can't welter you can't welter they can't welter
V-ing form
I can't be weltering you can't be weltering he can't be weltering we can't be weltering you can't be weltering they can't be weltering
Perfect
I can't have weltered you can't have weltered he can't have weltered we can't have weltered you can't have weltered they can't have weltered
V-ing perfect
I can't have been weltering you can't have been weltering he can't have been weltering we can't have been weltering you can't have been weltering they can't have been weltering
Interrogative form
Simple form
can I welter? can you welter? can he welter? can we welter? can you welter? can they welter?
V-ing form
can I be weltering? can you be weltering? can he be weltering? can we be weltering? can you be weltering? can they be weltering?
Perfect
can I have weltered? can you have weltered? can he have weltered? can we have weltered? can you have weltered? can they have weltered?
V-ing perfect
can I have been weltering? can you have been weltering? can he have been weltering? can we have been weltering? can you have been weltering? can they have been weltering?
Interro-negative form
Simple form
can't I welter? can't you welter? can't he welter? can't we welter? can't you welter? can't they welter?
V-ing form
can't I be weltering? can't you be weltering? can't he be weltering? can't we be weltering? can't you be weltering? can't they be weltering?
Perfect
can't I have weltered? can't you have weltered? can't he have weltered? can't we have weltered? can't you have weltered? can't they have weltered?
V-ing perfect
can't I have been weltering? can't you have been weltering? can't he have been weltering? can't we have been weltering? can't you have been weltering? can't they have been weltering?