我曾经历过一些很可怕的事情,它真真实实地发生过。 I have been through some terrible things in life, some of which actually happened我知道这是马克吐温的一句话,别人说是要珍惜现在的意思,可是我理解不了,请问是要怎么理解?望能说的具体点,能举例说明更好??~~还请高手指点~~~这厢有礼~\(≥▽≤)/~另外是出自哪里呢?