"O své babičce napsala knihu."

Translation: She wrote a book about her grandmother.

[Werner_Rietveld]

I wrote he and his instead of she and her. How can I see the difference?

[VladaFu]

Napsala is a feminine participle, the masculine form is napsal. You can review the Tips and notes of Past 1.

[VicCoca123]

"O své" sounds way too close to "osle"