If you cannot find a specific PDF, these tools cover the same material: : Flashcards for Chapter 1 vocabulary
Practical next steps (recommended)
Buy or borrow the Boya Chinese Elementary 1 Teacher’s Manual (2nd Edition). It includes not only workbook answers but also teaching objectives, additional drills, and cultural notes. Prices range from $25 to $40 USD. University libraries often have a copy in the reserve section. Boya Chinese Elementary 1 Workbook Answers Pdf
他昨天___来上课。 Correct answer: 没 (because 昨天 indicates past, and 没 negates past actions). If you cannot find a specific PDF, these