When writing or revising, do your intermediate and advanced students get confused about when to make the past participle agree? If so, then have them use this simple and handy flow chart!
They will start by asking themselves which helping verb. Then the chart will guide them through the questions they need to ask themselves to find out whether or not to make the past participle agree with either the subject or the COD (and when to not make it agree in certain pronominal verb cases).
In the end, they'll have their answer along with some examples to help clarify!