“They ride to the bookstore”的同义句有很多，以下是一些例子：

They journey to the bookstore.

They travel to the bookstore.

They head for the bookstore.

They make their way to the bookstore.

They go to the bookstore by bike.

这些句子都表达了相同的意思，即“他们骑自行车去书店”。请注意，虽然这些句子在表达上略有不同，但它们的核心意思保持不变。