Is Tungsten magnetic? I dropped my boyfriends ring (made of Tungsten) down the place in the doorframe where the door closes, not knowing there was actually a hole there.
Use commas to separate things in a list or series. If you have a series of three or more items, use commas to separate each item. Do not place commas before or after the list or series. Do not use commas when all the items in a series are linked by and, or, or nor.
Commas After Prepositional Phrases at the Beginning of a Sentence. When you start a sentence with a prepositional phrase, it's usually a good idea to put a comma after it (as in the examples above). In general, the longer the prepositional phrase, the more you need the comma.