I can trephine you can trephine he can trephine we can trephine you can trephine they can trephine
V-ing form
I can be trephining you can be trephining he can be trephining we can be trephining you can be trephining they can be trephining
Perfect
I can have trephined you can have trephined he can have trephined we can have trephined you can have trephined they can have trephined
V-ing perfect
I can have been trephining you can have been trephining he can have been trephining we can have been trephining you can have been trephining they can have been trephining
Negation
Simple form
I cannot trephine you cannot trephine he cannot trephine we cannot trephine you cannot trephine they cannot trephine
V-ing form
I cannot be trephining you cannot be trephining he cannot be trephining we cannot be trephining you cannot be trephining they cannot be trephining
Perfect
I cannot have trephined you cannot have trephined he cannot have trephined we cannot have trephined you cannot have trephined they cannot have trephined
V-ing perfect
I cannot have been trephining you cannot have been trephining he cannot have been trephining we cannot have been trephining you cannot have been trephining they cannot have been trephining
Interrogative form
Simple form
can I trephine? can you trephine? can he trephine? can we trephine? can you trephine? can they trephine?
V-ing form
can I be trephining? can you be trephining? can he be trephining? can we be trephining? can you be trephining? can they be trephining?
Perfect
can I have trephined? can you have trephined? can he have trephined? can we have trephined? can you have trephined? can they have trephined?
V-ing perfect
can I have been trephining? can you have been trephining? can he have been trephining? can we have been trephining? can you have been trephining? can they have been trephining?
Interro-negative form
Simple form
can I not trephine? can you not trephine? can he not trephine? can we not trephine? can you not trephine? can they not trephine?
V-ing form
can I not be trephining? can you not be trephining? can he not be trephining? can we not be trephining? can you not be trephining? can they not be trephining?
Perfect
can I not have trephined? can you not have trephined? can he not have trephined? can we not have trephined? can you not have trephined? can they not have trephined?
V-ing perfect
can I not have been trephining? can you not have been trephining? can he not have been trephining? can we not have been trephining? can you not have been trephining? can they not have been trephining?