I have just concluded a two-day business writing seminar at work, and it was great to be reoriented with my all-time favorite field of study in school: English grammar! I am by no means an expert, and although English is my second language, I have a pretty good grasp of the parts of speech, grammar and mechanics, sentence structures, and spelling. So let's have a fun little discussion on an otherwise dreaded subject. Consider the following. One of my sisters' friends is an actress. One of my sister's friends is an actress. One of my sister's friend is an actress. I'm willing to say that Sentences 1 and 2 are both correct in the use of possessives and apostrophes, but I have an issue with the third sentence. In the first sentence, the plural noun sisters has an apostrophe at the end, indicating that all of them have a common friend, i.e., their friend. Sentence 2 refers to only one sister having a friend, i.e., her friend. From my perspective, the third statement has an awkward sound and poor construction although it carries the same message as Number 2, which is "I have a sister who has a friend who is an actress." BUT it looks grammatically incorrect. Here's why. First, the phrase "one of," although singular in number, denotes one of many. Thus the object of the preposition of is plural in number (one of five, one of the computers, etc.). Second, in the given example Sentence 2, the phrase "one of" is linked to friends, which is the object of the preposition of. Whereas in the third example, "one of" points to sister's, which is a modifier of the noun friends. Yet I often hear this awkward construction from daily conversations or even read such format in print. One of my neighbors' cat is missing. What say you??? EDIT: My gramma taught me grammar. Sorry about the typo in the thread title. Mods, thanks for the correction.