“In” indicates position, place, or location.
- He kept telling Sam-I-Am that he does not like green eggs and ham whether they are in a tree, in a box, or in a house.
- If you give a mouse a cookie and then a glass of milk, he will eventually look in a mirror to make sure he doesn’t have a mustache.
“Into” indicates movement of something toward something else.
- Frustrated at being asked the same question over and over, Contrary Mary finally goes into her garden to see how it is growing.
- Alice and a talking white rabbit plunged into the rabbit hole and began a grand adventure.
“In to” relates preceding and following occurrences.
- The Seven Dwarfs walked in to find a beautiful maiden asleep inside their cottage.
- The Three Bears weren’t so lucky. They came in to discover a strange, golden-haired girl had eaten baby bear’s food, broken its little chair, and had fallen fast asleep in its comfy bed.