hanamaru
Describe a thing with a clause
A plain-form clause stands right in front of a noun and describes it: とった しゃしん, the photo someone took; こんが たべた ラーメン, the ramen Kon ate. The doer inside the clause takes が. There is no word for “that” or “which”.
JLPTN5
とった しゃしん · こんが たべた ラーメンtotta shashin
Japanese puts the description before the thing. Take a plain sentence — こんが ラーメンを たべた — drop the を-object out, and the rest goes in front of it: こんが たべた ラーメン. The verb stays in its plain form (た, る, ない, なかった); an い-adjective goes in front as it is: おいしい ラーメン. Inside the clause the subject takes が, never は: が marks who did it, は would make the whole noun phrase the topic. To a teacher the polite ending goes on the main verb at the end, not inside the clause: ぼくが とった しゃしんです.