I usually dislike giving only a website as an answer, but this page explains it far better (and funnier) than I could ever manage: http://theoatmeal.com/comics/apostrophe

NO - There are no differences. An apostrophe used to indicate possession is always written after the noun (it applies to both, whether it is animate or inanimate) and an "s" if it is singular. There are some exceptions though like: proper nouns ending in "s" and common nouns with the same singular and plural form (e.g. moose). Examples: 1. dog's tail (animate - common noun - singular) 2. violin's bow (inanimate - common noun - singular) 3. Webster's dictionary (inanimate - proper noun - singular) 4. angels' voices (animate - common noun - plural) 5. Titus, Cyrus, and James' swords (animate - proper noun - plural) *If there are two or more nouns who possess it, place the apostrophe ONLY to the nearest one. 6. sheep's wool (animate - common noun - singular/plural) If you have more questions just feel free to ask.

Here are some examples The boy's book. The book belonging to the boy. (one boy) The boys' books. The books belonging to the boys. (more than one boy) If the final s is forming a plural - which, it generally is, do not add another s. Only add the apostrophe. If the final s is not forming the plural, add the apostrophe and s as in the first example. Like this: The boss's book. There is only one boss. The plural of boss is bosses! The bosses' books. More than one boss. Some plurals don't use an s. The children's books. So the s after the apostrophe is needed. So, your examples: table leg - correct - we can refer to the leg of a table as a 'table leg' - we are describing the leg. The type of leg is a table leg. It is not a chair leg. table's leg - correct - the leg of the table Mary's book - correct Mary book - incorrect The other should be: application's interfaces - for one aplication applications' interfaces - for more than one application There is no difference between animate and inanimate. You can say: A human leg. The type of leg is human. A human's leg. A leg belonging to a human.

To answer your question.......no, there is no difference in how we express possession between the two. The following would be correct: 1(a) - Table's leg (somewhat correct, personifies the table, not common use/ see explanation below*) 1(b) - Table leg (correct, common use) 2(a) Mary's book (correct) 2(b) Mary book (not correct) 3(a) applications' interfaces (correct, when plural the apostrophe follows the "s") 3(b) applications interfaces (not correct) *In English, it does sound strange (although not grammatically incorrect) to express possession with inanimate objects. If you were to say "the computer's screen", it somewhat personifies the computer. A person can own (possess something), but, technically an inanimate thing cannot. The computer does not own the screen. :) Therefore, it is usually better to use the term as an descriptive adjective instead. Sometimes we can do this in English. Examples: 1. the computer screen 2. the table top 3. the television remote "Computer, table," and "television" are all used like descriptive adjectives. This is correct to do and much more common. I hope this helps!

The correct answers are 1 A 2 A 3 A Note that the placement of the apostrophe in the third example indicates that the applications are plural. Thus there are multiple applications which each have multiple interfaces. We could also say: The application's interface (one application which has one interface) The applications' interface (multiple applications which share the same interface) The applications' interfaces (multiple applications which each have multiple interfaces)