There is a book shop on the way to school.意思是说在经过学校的路上，有一个书店，但是并没有指定是哪一个学校，可能是某某小学，可能是某某医学院。 There is a book shop on the way to the school.意思是已经指定了某一所学校（例如：师范1小），那么这整个的句子的意思就是：有一家书店在去那所学校的路上（在去师范1小的路上）。 2个的区别就是一个没有指定究竟是哪所学校，而另一个指定了。

the school = 那個學校 (the = 定冠詞/"definite article", 表示一個具體的學校；a particular school) a school ＝ 一個學校 (a = 定冠詞/"indefinite article", 表示一個學校，一般而言；a school, generally speaking) 其實，如果是具體的學校，不得加‘the'，我們喜歡簡單地說”on the way to school"，這是平常的說法，也常常聽說“going to work”， 或 “on the way to work”。

Yes, like Eliot said there is not much difference. Saying "the school" is more specific, but the meaning is the same.

Not much difference. It really depends if you are going to school or going to the school. Same rule applies.