我把句子翻译出来，网友对号入座即可：

She was s gifted writer. Her next two books were also about the oceans and both topped the book sales lists.

她是个有天赋的作家。她接下来的两本书也是关于海洋的，（两本书）都在图书销售排行榜上名列前茅。

both （主语） topped （谓语动词）the book sales lists（宾语）.

the book sales lists：名词词组。“图书销售排行榜”。