1. We see through/with our eyes.
2. We eat through/with our mouth.
3. We run through/with our legs.
4. We talk through/with our mouth.
5. We breathe through/with our nose.
(Would you check the sentences? Which preposition do I have to use? Are both OK?)
6. Don't break off the branches.
6-2. Don't break away the branches.
(Can we use 'away' as in 6-2?)
7. Please make up your own character.(in a comic book)
7-2. Please _________ your own character.
(What other expressions can we use instead of 'make up'?)
1 - 5 -- The preposition "with" is better with all of these.
6 is better than 6-2.
7 is fine. Other verbs/experessions you can use are create, devise, invent ...
Well, in sentence 5, you could use either preposition!!