Mistake 1: Assuming every wāw is a coordinating wāw, without checking meaning.
Mistake 2: Calling Khālidan in raʾaytu Zaydan wa-Khālidan a subject: both nouns are in the direct-object relation.
Mistake 3: Treating anā in ḍarabtu anā wa-Zaydun as a second independent subject. It reinforces the attached subject pronoun.
Mistake 4: Calling the second bi- in marartu bika wa-bi-Zaydin unnecessary: the book explicitly requires its repetition in this construction.