Complex sentence: If two torsion-free abelian groups have the same type they are isomorphic, so there is a bijection between types of torsion-free abelian groups of rank 1 and their isomorphism classes, providing a complete classification.
Split into simpler sentences: If two torsion-free abelian groups of rank 1 have the same type they may be shown to be isomorphic. Hence there is a bijection between types of torsion-free abelian groups of rank 1 and their isomorphism classes, providing a complete classification.