Complex sentence: Clayton & Black were commissioned to execute the School Board's "grandiose plans" for three blocks accommodating about 1,200 children and associated facilities; limited finances meant the plans had to be redesigned, and the firm provided for a single block for 580 children.
Split into simpler sentences: Clayton & Black were commissioned to execute the School Board's "grandiose plans" for three blocks accommodating about 1,200 children and associated facilities. Limited finances meant the plans had to be redesigned, and the firm provided for a single block for 580 children.