What does it mean to truly grow up?

The black night was split open like the coconut

Phosgene is a chemical agent that is formed by decomposition of chlorinated hydrocarbon solvents by ultraviolet radiation.

Which sentence is punctuated correctly? the shoes normally cost 40 dollars, however; we got them on sale. the shoes normally cost 40 dollars however we got them on sale. the shoes normally cost 40 dollars, however, we got them on sale. the shoes normally cost 40 dollars; however, we got them on sale.