Some state libraries provide free access to e-textbooks if you have a valid library card. Check your local library’s "eResource" database. Archives like (archive.org) may have older editions available for 14-day borrowing (not download).
: Each unit follows a consistent "one page, one lesson" format, making it easy for teachers to plan and for students to follow. Skill Integration English Plus 1 Textbook Pdf
It is widely adopted in national curricula across the globe, notably in and various international schools in Eastern Europe and the Middle East. Some state libraries provide free access to e-textbooks
Due to the pandemic, many ministries of education purchased national licenses. Ask your teacher: one lesson" format