1 in a serious way 严重；严肃；认真: Three people were seriously injured in the accident. 这起事故中有三人受重伤。My mother is seriously ill. 我妈妈病得很重。It's time you started to think seriously about the future. 是该认真考虑你的前途的时候了。

2 used at the beginning of a sentence for showing that you are not joking or that you really mean what you are saying （用于句首，表示认真）说真的，真的，说正经的: Seriously, I do appreciate all your help. 说正经的，我真的感激你的帮忙。Seriously, you've got nothing to worry about. 说真的，你没有什么可担心的。

3 used for expressing surprise at what sb has said and asking if it is really true （用于表示对某人所说的感到惊奇，并求证是否属实）说真的，真的: ‘I'm 40 today.’ ‘Seriously? You look a lot younger.’ “我今天40岁了。”“真的吗？你看来年轻多了。”