Complex sentence: The school year in Russia traditionally starts on September 1 ("The Knowledge Day ") and lasts until 25 May, which is also known as"The Last School-Bell" day celebrated by the graduates, their families and teachers.
Split into simpler sentences: The school year in Russia traditionally starts on September 1 ("The Knowledge Day "). Generally the school year lasts until 25 May, which is also known as"The Last School-Bell" day celebrated by the graduates, their families and teachers.