These are new words used in the dialogue. Try to memorize them.
1. マジック marker pen 2. 買(か)い [V-stem of かいます "buy"] 3. に [V-stem + に] for (V-ing), to (V); [X + に] for (the purpose of/the use of) X 4. ぶんぼうぐ屋(や) stationery store 5. 買(か)いに行って [V-てform of かいに いきます "go (somewhere) in order to buy (something)"] 6. がようし construction paper 7. 買(か)ってきて [Errand pattern] buy and come back 8. 下(くだ)さいませんか Won't you give me? [下さいます "give me/us"; Vて下さいませんか "Won't you please V?"] 9. なんまい how many sheets [of thin, flat objects]? 10. ぶんかさい school festival 11. ポスター poster