监：通“鉴”，照，察；貌：容色，外表；辨：辨别，明察；色：脸色。通过观察脸色来辨别对方的心思。形容为人机灵
try to read somebody's mind by watching his facial expression
监(jiān jiàn)
貌(mào)
辨(biàn)
色(sè)
