used to imply in an ironic or resigned way that someone's wishes or expectations are unlikely to be fulfilled
恐怕是不可能的
‘A shirt would be nice.’ ‘You'll be lucky.’.
“要是有一件衬衫就好了。”“不大可能吧。”。
used to express envy at someone else's good fortune
幸运的家伙(表达对别人好运的嫉妒)