I recently edited a manuscript that was rife with sentences combined with the word “then.” Like this one: She pulled the lever, allowing the big steel blades to catch the wind. At first nothing came then finally a small trickle of water splashed into the trough . My red pencil itches to add a comma. It’s two separate actions. The “and” seems to be understood and to me is redundant. At first nothing came, and then finally a small trickle of water splashed into the trough . If you use “and,” do you even need “then?” But in this case, “and” just doesn’t say the same thing. According to grammar gurus, this is called a “comma splice” and is supposedly a no-no. As one grammarian put it, “It feels so right. It flows so well. It looks so pretty. But technically, it’s as wrong as wearing wooly socks with strappy summer sandals.” This same source reminds us of an acronym to remember what a coordinating conjunction is: FANBOYS : F or- A nd- N or- B ut- O r- Y et- S o. But, she says, be careful of...