Definition: Given the Question and Answer pair, detect whether the answer is acceptable or not. Denote acceptable answer as "yes", otherwise denote as "no". An acceptable answer is consistent with the context in question, detailed, long, and uses general knowledge of English. Answers that are not definite and suggest a variety of options are not acceptable answers.
Input: Question: Possible Duplicate: What is the correct possessive for nouns ending in s? Before you vote to close as a duplicate, note that these two questions deal with similar issues to this, but none of them address all three criteria of this question: The singular already ends with an s. I am dealing with multiple of the thing. I want the possessive of all of them in general. The singular is class, and the plural is classes. The singular possessive is class's (as addressed here). What is the plural possessive? Is it classes's, or classes'? 
Answer: It is classes', which sounds the same as the singular class's. I would have thought this was a general rule for plural nouns ending -s', -es' or -ies'.

yes