https://englishfile4e.oxfordonlinepractice.com/app/dashboard/book/100/unit/07/lesson/01/activity/06 

https://quillbot.com/ 

https://www.youtube.com/watch?v=T5OHp05XUOg 

https://englishpracticetest.net/practice-english-reading-tests-for-b1-with-answer/ 

https://www.letras.com/music-and-lyrics/promesas/#radio:music-and-lyrics 

https://learnenglish.britishcouncil.org/vocabulary/b1-b2-voc 

https://yosoytuprofe.20minutos.es/2018/09/19/100-problemas-de-ecuaciones-de-primer-grado-resueltos/