Schubert publishing offers a B1/B2 grammar book with online exercises. Many Goethe-Institut libraries have free digital access to this.
– many libraries offer e‑lending services (e.g., OverDrive, Libby, Onleihe) where you can borrow the digital version for free. --- Pons 600 ubungen Deutsch Als Fremdsprache Pdf
Why is the PDF search term so popular? There are three psychological drivers: Schubert publishing offers a B1/B2 grammar book with