I can invigilate you can invigilate he can invigilate we can invigilate you can invigilate they can invigilate
V-ing form
I can be invigilating you can be invigilating he can be invigilating we can be invigilating you can be invigilating they can be invigilating
Perfect
I can have invigilated you can have invigilated he can have invigilated we can have invigilated you can have invigilated they can have invigilated
V-ing perfect
I can have been invigilating you can have been invigilating he can have been invigilating we can have been invigilating you can have been invigilating they can have been invigilating
Negation
Simple form
I cannot invigilate you cannot invigilate he cannot invigilate we cannot invigilate you cannot invigilate they cannot invigilate
V-ing form
I cannot be invigilating you cannot be invigilating he cannot be invigilating we cannot be invigilating you cannot be invigilating they cannot be invigilating
Perfect
I cannot have invigilated you cannot have invigilated he cannot have invigilated we cannot have invigilated you cannot have invigilated they cannot have invigilated
V-ing perfect
I cannot have been invigilating you cannot have been invigilating he cannot have been invigilating we cannot have been invigilating you cannot have been invigilating they cannot have been invigilating
Interrogative form
Simple form
can I invigilate? can you invigilate? can he invigilate? can we invigilate? can you invigilate? can they invigilate?
V-ing form
can I be invigilating? can you be invigilating? can he be invigilating? can we be invigilating? can you be invigilating? can they be invigilating?
Perfect
can I have invigilated? can you have invigilated? can he have invigilated? can we have invigilated? can you have invigilated? can they have invigilated?
V-ing perfect
can I have been invigilating? can you have been invigilating? can he have been invigilating? can we have been invigilating? can you have been invigilating? can they have been invigilating?
Interro-negative form
Simple form
can I not invigilate? can you not invigilate? can he not invigilate? can we not invigilate? can you not invigilate? can they not invigilate?
V-ing form
can I not be invigilating? can you not be invigilating? can he not be invigilating? can we not be invigilating? can you not be invigilating? can they not be invigilating?
Perfect
can I not have invigilated? can you not have invigilated? can he not have invigilated? can we not have invigilated? can you not have invigilated? can they not have invigilated?
V-ing perfect
can I not have been invigilating? can you not have been invigilating? can he not have been invigilating? can we not have been invigilating? can you not have been invigilating? can they not have been invigilating?