I can landmark you can landmark she can landmark we can landmark you can landmark they can landmark
V-ing form
I can be landmarking you can be landmarking she can be landmarking we can be landmarking you can be landmarking they can be landmarking
Perfect
I can have landmarked you can have landmarked she can have landmarked we can have landmarked you can have landmarked they can have landmarked
V-ing perfect
I can have been landmarking you can have been landmarking she can have been landmarking we can have been landmarking you can have been landmarking they can have been landmarking
Negation
Simple form
I cannot landmark you cannot landmark she cannot landmark we cannot landmark you cannot landmark they cannot landmark
V-ing form
I cannot be landmarking you cannot be landmarking she cannot be landmarking we cannot be landmarking you cannot be landmarking they cannot be landmarking
Perfect
I cannot have landmarked you cannot have landmarked she cannot have landmarked we cannot have landmarked you cannot have landmarked they cannot have landmarked
V-ing perfect
I cannot have been landmarking you cannot have been landmarking she cannot have been landmarking we cannot have been landmarking you cannot have been landmarking they cannot have been landmarking
Interrogative form
Simple form
can I landmark? can you landmark? can she landmark? can we landmark? can you landmark? can they landmark?
V-ing form
can I be landmarking? can you be landmarking? can she be landmarking? can we be landmarking? can you be landmarking? can they be landmarking?
Perfect
can I have landmarked? can you have landmarked? can she have landmarked? can we have landmarked? can you have landmarked? can they have landmarked?
V-ing perfect
can I have been landmarking? can you have been landmarking? can she have been landmarking? can we have been landmarking? can you have been landmarking? can they have been landmarking?
Interro-negative form
Simple form
can I not landmark? can you not landmark? can she not landmark? can we not landmark? can you not landmark? can they not landmark?
V-ing form
can I not be landmarking? can you not be landmarking? can she not be landmarking? can we not be landmarking? can you not be landmarking? can they not be landmarking?
Perfect
can I not have landmarked? can you not have landmarked? can she not have landmarked? can we not have landmarked? can you not have landmarked? can they not have landmarked?
V-ing perfect
can I not have been landmarking? can you not have been landmarking? can she not have been landmarking? can we not have been landmarking? can you not have been landmarking? can they not have been landmarking?