英文俚语flashback , croak , loser什麼意思,怎样运用?

flashback = 急转 http://dict.cn/search/?q=flashback
同于：hindsight, memoir, recall, recollection, reconsideration, reflection, remembrance, reminiscence, retrospect, retrospection, review

croak = 嗄嗄声,哇哇声 http://dict.cn/search/?q=croak

loser （北美口语）失败者,遗失者 http://dict.cn/search/?q=loser
同于：total loss;stooge; underdog; fall guy;
The hardest thing to learn is to be a good loser.=最难学的一点是做一个输的起的人。
He always gets annoyed when I beat him at cards; he's a bad loser.=每当我打牌赢了他时，他总是很生气，他是个输不起的人。