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Tobira Grammar Power: Exercises for Mastery complements the Tobira textbook with additional resources to practice the grammar introduced in the textbook. This book contains 10-15 pages of exercises per chapter, giving you plenty of material to practice and improve your grammar. The exercises gradually get harder the deeper you get into a chapter. The start of a chapter typically has easier exercises like for example "Insert the appropriate particle", but it gets harder quickly with challenges like writing small essays.
Tobira: Gateway to Advanced Japanese (Learning through Content and Multimedia)
Tobira: Gateway to Advanced Japanese Power Up Your Kanji