I can grieve you can grieve he can grieve we can grieve you can grieve they can grieve
V-ing form
I can be grieving you can be grieving he can be grieving we can be grieving you can be grieving they can be grieving
Perfect
I can have grieved you can have grieved he can have grieved we can have grieved you can have grieved they can have grieved
V-ing perfect
I can have been grieving you can have been grieving he can have been grieving we can have been grieving you can have been grieving they can have been grieving
Negation
Simple form
I cannot grieve you cannot grieve he cannot grieve we cannot grieve you cannot grieve they cannot grieve
V-ing form
I cannot be grieving you cannot be grieving he cannot be grieving we cannot be grieving you cannot be grieving they cannot be grieving
Perfect
I cannot have grieved you cannot have grieved he cannot have grieved we cannot have grieved you cannot have grieved they cannot have grieved
V-ing perfect
I cannot have been grieving you cannot have been grieving he cannot have been grieving we cannot have been grieving you cannot have been grieving they cannot have been grieving
Interrogative form
Simple form
can I grieve? can you grieve? can he grieve? can we grieve? can you grieve? can they grieve?
V-ing form
can I be grieving? can you be grieving? can he be grieving? can we be grieving? can you be grieving? can they be grieving?
Perfect
can I have grieved? can you have grieved? can he have grieved? can we have grieved? can you have grieved? can they have grieved?
V-ing perfect
can I have been grieving? can you have been grieving? can he have been grieving? can we have been grieving? can you have been grieving? can they have been grieving?
Interro-negative form
Simple form
can I not grieve? can you not grieve? can he not grieve? can we not grieve? can you not grieve? can they not grieve?
V-ing form
can I not be grieving? can you not be grieving? can he not be grieving? can we not be grieving? can you not be grieving? can they not be grieving?
Perfect
can I not have grieved? can you not have grieved? can he not have grieved? can we not have grieved? can you not have grieved? can they not have grieved?
V-ing perfect
can I not have been grieving? can you not have been grieving? can he not have been grieving? can we not have been grieving? can you not have been grieving? can they not have been grieving?