This study aims to examine how to describe the three different usages of V-ing forms in English: gerunds, present participles, action nominals, which are each illustrated as I enjoy watching TV, I was watching TV, and Avoid excessive watching of TV in order. Many grammarians tend to describe gerunds and present participle as one category of ``V-ing`` avoiding using their names, which results in a critical problem of making it impossible to explain different usages between gerunds and present participles (e.g., a sleeping car and a sleeping boy). Also, many school grammar books tend to describe gerunds and action nominals as one category of ``gerund`` despite the fact that there are various differences between the two. For example, action nominals needs of after them but gerunds do not, action nominals can have determiners before them but gerunds cannot, action nominals can be modified by adjectives but gerunds cannot, and so on. These trends of describing different items as one category are likely to make school grammar more complicated than simplified. We need to distinguish them since they are different. Moreover, we have simple ways to distinguish them. Present participles have progressive meaning in them, but gerunds do not. Gerunds have a verb-like property but action nominals have a noun-like property.