If you are struggling with a specific video segment in 5.7, try slowing the playback speed to 0.75x. This allows you to see the transition between signs, which is often where the "answers" to the comprehension questions are hidden.
In English, we add "-ed" to verbs to show past tense. In ASL, you change the movement of the sign. For example: Signing Naturally Unit 5.7 Answer Key Extra Quality