quantum leap
noun [ C usually singular ] uk/ˌkwɒn.təm ˈliːp/ us/ˌkwɑːn.t̬əm ˈliːp/
飞跃，重大进展
a great improvement or important development in something
The appointment of a female director is a quantum leap for women's equality. 任命一名女局长从男女平等方面来说是个大飞跃。