Questions 11–17: identify the correct possessive form. 11. his sister’s-in-law/sister-in-law’s letter came as a surprise to chuck. 12. arizona’s/arizonas’ climate is dry. 13. she is writing a paper on byron and shelley’s/byron’s and shelley’s poems. 14. i met a man whose/who’s sister i know. 15. it’s too bad that the dog’s/dogs’ foot got hurt. 16. smith’s/smiths’ house is red. 17. kevin and mike’s/kevin’s and mike’s parents, arthur and alice brooks, are both scientists.

11. His sister-in-law’s letter came as a surprise to Chuck.

The compund noun is not separated. The 's is added to the end of the noun.

12. Arizona’s climate is dry.

The possessive of a singular noun is formed by adding an 's to it.

13. She is writing a paper on Byron’s and Shelley’s poems.

Since the poems belong to two separate people--they did not compose them together, so this is not shared ownership--the 's goes after each of their names.

14. I met a man whose sister I know.

Who's is a contraction meaning "who + is", expressing "what or which person or people". Whose is a possessive pronoun.

15. It’s too bad that the dog’s foot got hurt.

This is the same case as number 12.

16. Smith’s house is red.

If a singular noun ends in s, the rule is to also add 's. The only time a noun ending in s will only have an apostrophe added is when is plural. So in this case it could only be Smith's or Smiths's, depending on the name, since it's not a plural noun.

17. Kevin and Mike’s parents, Arthur and Alice Brooks, are both scientists.

Kevin and Mike share the same parents. As this is a shared possessive, the 's goes at the end of the last name.

an old person

explanation: