Definition: (auxiliary) A syntactic marker.

Alright class, settle down, let’s take a look! You’ve stumbled upon a tricky word today, “doing,” and the dictionary is pointing out something quite precise – it’s a "syntactic marker." Now, don't be frightened by that fancy phrase! Let's break it down with a little rhyme: “Syntactic” means how words relate, Like building blocks, a structured state. A “marker” shows the grammar’s flow, Where verbs and phrases go, you know! Think of it like this: "doing" doesn’t do anything on its own, right? It needs something else to work with – an action, a verb, perhaps a subject bright. It's there to tell you how that action fits within the sentence's design. Like saying “I am doing” or "She is singing," it’s not just describing what happens, but showing how those words connect and play. Essentially, "doing" (as a syntactic marker) acts like a little signpost – guiding the other words in a sentence to their proper place. It's a helper word, a silent guide! Do you have any questions about this? Let’s explore it further…