I can landmark you can landmark he can landmark we can landmark you can landmark they can landmark
V-ing form
I can be landmarking you can be landmarking he can be landmarking we can be landmarking you can be landmarking they can be landmarking
Perfect
I can have landmarked you can have landmarked he 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 he can have been landmarking we can have been landmarking you can have been landmarking they can have been landmarking
Negation
Simple form
I can't landmark you can't landmark he can't landmark we can't landmark you can't landmark they can't landmark
V-ing form
I can't be landmarking you can't be landmarking he can't be landmarking we can't be landmarking you can't be landmarking they can't be landmarking
Perfect
I can't have landmarked you can't have landmarked he can't have landmarked we can't have landmarked you can't have landmarked they can't have landmarked
V-ing perfect
I can't have been landmarking you can't have been landmarking he can't have been landmarking we can't have been landmarking you can't have been landmarking they can't have been landmarking
Interrogative form
Simple form
can I landmark? can you landmark? can he landmark? can we landmark? can you landmark? can they landmark?
V-ing form
can I be landmarking? can you be landmarking? can he be landmarking? can we be landmarking? can you be landmarking? can they be landmarking?
Perfect
can I have landmarked? can you have landmarked? can he 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 he have been landmarking? can we have been landmarking? can you have been landmarking? can they have been landmarking?
Interro-negative form
Simple form
can't I landmark? can't you landmark? can't he landmark? can't we landmark? can't you landmark? can't they landmark?
V-ing form
can't I be landmarking? can't you be landmarking? can't he be landmarking? can't we be landmarking? can't you be landmarking? can't they be landmarking?
Perfect
can't I have landmarked? can't you have landmarked? can't he have landmarked? can't we have landmarked? can't you have landmarked? can't they have landmarked?
V-ing perfect
can't I have been landmarking? can't you have been landmarking? can't he have been landmarking? can't we have been landmarking? can't you have been landmarking? can't they have been landmarking?