This is a key （ ）（ ）（ ）（ ）.

This is a key （ ）（ ）（ ）（ ）.

These are the keys.

What is the plural of photo, key, pear?

photo ['fəutəu]
n. Photos
[plural photos]
key [ki:]
n. The key of a typewriter, etc
Vt. type; lock; adjust The tone of; provide clues
Vi. using keys
Key
[plural keys]
Pear complex

It's said in the book that the vowel + O usually ends with S. but the plural of photo memo piano also ends with S
It's said in the book that the vowel + O usually ends with S. but the plural of photo memo piano also ends with S

There are five vowels a, e, I, O, u in total. The plural form of the words ending with them is plus s, but there is a slight exception in O. if the words ending with o are living things, such as potato, add es, and if they are inanimate things, add S. all the above examples are inanimate photos, so add s