To and At.
(a) To.
Not OK: We come at school every morning.
Say: We come to school every morning.
(b) At.
Not OK: Chewbacca is standing to the door.
Say: Chewbacca is standing at the door.
To and Till.
(a) To.
Not OK: Jar Jar walked till the river and back.
Say: Jar Jar walked to the river and back.
(b) Till.
Not OK: The Jedi [...]