Lesson 16 - around, because, before, bring, carry, light, show, think

Lesson 17 - about, could, sure, by, don't, maybe, there, car 

Lesson 18 - first, right, under, food, sometimes, your, ground, these

Lesson 19 - done, paper, were, great, soon, work, laugh, talk

Lesson 20 - door, old, want, more, try, wash, mother, use