As a general rule, 'in' and 'on' express position, and 'into' and 'onto' express movement. Position: We were sitting IN the café. She stood ON the balcony. Movement: We went INTO the café. She walked ONTO the balcony. We sometimes use 'in' and 'on' for movement, especially in informal English: We went in the café. The opposite of 'into' is 'out of': 'She got out of the car and went into a shop.'

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