I can lower you can lower he can lower we can lower you can lower they can lower
V-ing form
I can be lowering you can be lowering he can be lowering we can be lowering you can be lowering they can be lowering
Perfect
I can have lowered you can have lowered he can have lowered we can have lowered you can have lowered they can have lowered
V-ing perfect
I can have been lowering you can have been lowering he can have been lowering we can have been lowering you can have been lowering they can have been lowering
Negation
Simple form
I can't lower you can't lower he can't lower we can't lower you can't lower they can't lower
V-ing form
I can't be lowering you can't be lowering he can't be lowering we can't be lowering you can't be lowering they can't be lowering
Perfect
I can't have lowered you can't have lowered he can't have lowered we can't have lowered you can't have lowered they can't have lowered
V-ing perfect
I can't have been lowering you can't have been lowering he can't have been lowering we can't have been lowering you can't have been lowering they can't have been lowering
Interrogative form
Simple form
can I lower? can you lower? can he lower? can we lower? can you lower? can they lower?
V-ing form
can I be lowering? can you be lowering? can he be lowering? can we be lowering? can you be lowering? can they be lowering?
Perfect
can I have lowered? can you have lowered? can he have lowered? can we have lowered? can you have lowered? can they have lowered?
V-ing perfect
can I have been lowering? can you have been lowering? can he have been lowering? can we have been lowering? can you have been lowering? can they have been lowering?
Interro-negative form
Simple form
can't I lower? can't you lower? can't he lower? can't we lower? can't you lower? can't they lower?
V-ing form
can't I be lowering? can't you be lowering? can't he be lowering? can't we be lowering? can't you be lowering? can't they be lowering?
Perfect
can't I have lowered? can't you have lowered? can't he have lowered? can't we have lowered? can't you have lowered? can't they have lowered?
V-ing perfect
can't I have been lowering? can't you have been lowering? can't he have been lowering? can't we have been lowering? can't you have been lowering? can't they have been lowering?