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 cannot lower you cannot lower he cannot lower we cannot lower you cannot lower they cannot lower
V-ing form
I cannot be lowering you cannot be lowering he cannot be lowering we cannot be lowering you cannot be lowering they cannot be lowering
Perfect
I cannot have lowered you cannot have lowered he cannot have lowered we cannot have lowered you cannot have lowered they cannot have lowered
V-ing perfect
I cannot have been lowering you cannot have been lowering he cannot have been lowering we cannot have been lowering you cannot have been lowering they cannot 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 I not lower? can you not lower? can he not lower? can we not lower? can you not lower? can they not lower?
V-ing form
can I not be lowering? can you not be lowering? can he not be lowering? can we not be lowering? can you not be lowering? can they not be lowering?
Perfect
can I not have lowered? can you not have lowered? can he not have lowered? can we not have lowered? can you not have lowered? can they not have lowered?
V-ing perfect
can I not have been lowering? can you not have been lowering? can he not have been lowering? can we not have been lowering? can you not have been lowering? can they not have been lowering?