https://eduschool40.blog/%d8%ac%d9%85%d9%84%d8%a9-%d8%a7%d9%84%d8%aa%d9%86%d8%a7%d9%82%d8%b6-clause-of-contrast-%d9%81%d9%8a-%d8%a7%d9%84%d9%84%d8%ba%d8%a9-%d8%a7%d9%84%d8%a7%d9%86%d8%ac%d9%84%d9%8a%d8%b2%d9%8a%d8%a9/