prevent from 和save from

save A from B 的含义是使A免于受到B的损伤、损失或毁坏
e.g. The firemen save the girl from the fire.

prevent from防止某人做某事
e.g. Our enemies prevent us from winning.

save from:挽救， 免于
eg: the three Red Army men lived in a small village save from danger.这三位红军战士住在一个美誉危险的小村子里。
Lord, save me from my fear.上帝，救我于惊恐之中把！

prevent from防止某人做某事/防止某人做某事
eg.I was prevented from going by urgent business.
我因急事不能去。
You should prevent from the thieves.
你当然应该防备小偷.