
"Into" = movement toward the inside or transformation; "in to" = when "in" is part of a phrasal verb and "to" belongs to the following verb.
"Into" (one word) is the preposition of movement toward the inside or of transformation. "Walk into the room" = enter the room. "Turn into a frog" = transform and become a frog.
She walked into the room and immediately noticed something was different.
The caterpillar transforms into a butterfly during its metamorphosis.
He ran into his old professor at the grocery store on Saturday.
"In to" (two words) appears when "in" is part of a phrasal verb like "turn in", "log in", or "give in", and "to" belongs to the next verb. "I went in to eat" = I entered in order to eat.
Please come in to sign the final documents before you leave.
She turned her essay in to the professor five minutes before the deadline.
We logged in to check our account balances and found a suspicious transaction.
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The same "one or two words" principle applies to the pair ONTO / ON TO, which works exactly the same way. "Onto" is a preposition of movement toward a surface: "she climbed onto the roof." "On to" is "on" as part of a phrasal verb plus "to": "hold on to your dreams", "pass it on to the next person." If you can move "on" to the end of the sentence, use two words. "She held on" (works, "hold on" is a phrasal verb) → "hold on to your dreams" = two words. "She climbed on" doesn't work with the same sense → "climbed onto the roof" = one word.
Exercise 1 · Pick the right one
She walked _____ the room quietly and sat down.
Exercise 2 · Pick the right one
She came _____ sign the contract. She was in and out in five minutes.
Exercise 3 · Form the word
"Apart" = separated, at a distance; "a part" = a piece or member of something larger.
"Everyday" (one word) is an adjective meaning ordinary or daily; "every day" (two words) means each day.
One means to receive or agree to something, the other means to exclude or not include.
'Advice' is the guidance you receive (noun); 'advise' is the act of giving that guidance (verb).
Bryan López
Founder of SpeakUP Academy