When you're invited for 7:00中,为什么用for而不用at?

翻译题：When you're invited for 8:00,you're supposed to come later. When you're invited for 7:00中,为什么用for而不用at? When shall I arrive at my friend's house for dinner?When you're invited for 6:00,you're supposed to come_____（early or earlier) when you're gone when you're invited for 7:00,you are supposed to come later此句的for能不能改成at?这句中的for的用法? When you're gone歌词 when you're gone意思 When You'Re Ready 歌词 Bring you up when you're feeling you kooks cuter when you're When you're feeling lost inside,you're not alone When you're feeling lost inside,you're not alone 求艾薇儿《when you're gone》歌词翻译 求when you're gone 的英文歌词 Call Me When You're Sober 歌词 艾薇儿的When you're gone 中文歌词 艾薇儿 WHEN YOU~RE GONE歌词 When you're gone!是啥意思? when you 're feeling down and low