Complex sentence: In the first years of Bälinge IF's history their sportsmen wore blue and yellow dresses, these colors can only be used by a Swedish National Team so they had to switch to black and yellow.
Split into simpler sentences: In the first years of Bälinge IF's history their sportsmen wore blue and yellow team colours. It was then decided that these colors could only be used by a Swedish National Team so BIF had to switch to black and yellow.