Enjoy these fun extension activities based on the N2Y High-Frequency Word lists for Unit 19, Fast and Slow, Earth Changes. Six mystery pictures are included: four with 3 words per page and two with 6 words, separated by List 1 and List 2 in the N2Y unit. These may also be used for sight word work. List 1: an, some, will, kind, of, intoList 2: over, fast, water, must, ground, change Answer Keys Included.