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.
You already know you don't want to read a speech verbatim from a screen or notes. You could memorize the speech word-for-word, but not everyone is able to do that—and it isn't natural. Instead, use "key images" to remember your important points.