以
以 – Yi3 – Use, According To
This word is part of an expression that Jenny gave me as my “expression of whenever she feels like teaching me one” the other day.
以為 – Yi3 Wei2 – Believe, Consider That.
我以為你是豬 – Wo3 Yi3 Wei2 Ni3 Shi4 Zhu1 – I think you’re a pig.
(That is the same 為 that appears in Why and Because.)