Quirk in his A Comprehensive Grammar of English Dictionary objects the distinction between gerund and present participle. For reasons of his objection, you can check in his dictionary. but i myself consider it useful, though not necessarily necessary, to cling to this distinction, for it can make us more clear. and the differences do exist in "he is interesting" and "he is interesting us"; "he is washing" and "his job is washing"; "a sleeping boy" and "a sleeping bag". As a matter of fact, i have just graduated from a normal university in China and is trying to write a handbook for my students, hoping that it will facilitate their understanding of the English grammar in a pleasant and clear way. Thank you very much for your instructions. and any further help will be heartfeltly appreciated.

right as you are, how can you help the junior middle school students make sense of it? and there are other differences, such as in "a walking man" and "a walking stick". Hope to get your insightful ideas on how to make the students grasp this easily.