A big difference between our education and the education in other countries
A big gap between our education and the education of other countries
「差」は①のように "difference"と言ってもいいし、②のように”gap"と言ってもいいと思います。そして「他国の教育」は "the education in other countries"でも"the education of other countries"でもどちらでもいいです。
"If we didn't have internet, there would be a big difference between our education and the education in other countries"
「インターネットがなかったら自分たちの教育と他国の教育の間で差がつく」という意味です。
There is a big difference between our education system and that in other countries
There are significant differences between our education system and that in other countries
この文章が以下のように翻訳されています。
他国の教育と大きく差がつく ー There is a big difference between our education system and that in other countries
他国の教育 ー that in other countries
と ー (between our education system) and
大きく差がつく ー there is a big difference / there are significant differences
参考になれば嬉しいです。