This is a great chart for different grammar students may come upon when writing or editing/revising. (Makes a great anchor chart as well). I picked this chart because it is clear cut, easy to read, and would catch students' eyes if I were to color it up.
Shades of Modality [infographic]: A modal verb is a type of auxiliary verb that expresses possibility, necessity or obligation. Because of their commanding tone, modals must be used carefully, and some writers attempt to avoid them entirely.
Having the prepositions of time listed and in sections is nice. But I would also have more graphic examples. I would make a worksheet where the students matched examples to the appropriate preposition of time.