[书面语] Ⅰ动词 (是; 就是; 实在是) be; be really; be indeed 短语和例子 失败乃成功之母。 failure is the mother of success.Ⅱ副词 1.(于是) so; therefore; hence 短语和例子 因山势高峻, 乃在山腰休息片时。 it was a steep climb, so we rested for a while halfway up the hill.2.(才) only then 短语和例子 今乃知之。 i didn't know it until now. 惟虚心乃能进步。 you can make progress only if you are modest.Ⅲ代词 (你; 你的) you; your 短语和例子 乃父your father