Lest, In case, For fear 以免(英文的用法

lest 以免(最正式,而且竟然是連接詞!
for fear of 以免
for fear that 以免(sewage 污水 ,關於這個報導:https://www.youtube.com/watch?v=iuVu8WsH050
in case 為免萬一(
in case of 為免萬一(