You want to add the suffix ed to the following words which word would require you to change the y to an i?

Betray, destroy, and obey do not need to be changed to add the suffix -ed, because the "y" at the end of each word is preceded by a vowel  (so  they would be spelled  "betrayed," "destroyed," and "obeyed").

but hurry is different; it has to  be spelled "hurried" because the "y" at the end of "hurry" is preceded by a consonant.

Example :
when you have one it's family,but when you have two it's families.

The songs were performed with the singers' eyes closed so they could focus on the words and preserve every detail.

Students and school are nouns
good luck!