When I taught high school English, I used to rattle off a list of words my students should attempt not to use. They included is, be, am, are, was, were, being, been, have, has, had, do, did, does, may, might, can, could, shall, should, will, would. All of these can be used as helping herbs and all of these are very weak verbs when used by themselves. It was an effort to get them to really look at what they were writing.