Complex sentence: Again, care should be taken not to infer too many complex ideas of social history from grave sites, but they do show that people had surplus time for the production of decorative items and they hint at early beliefs about death and religion.
Split into simpler sentences: Again, care should be taken not to infer too many complex ideas of social history from grave sites. However, graves do show that people had surplus time for the production of decorative items and they hint at early beliefs about death and religion.