when: [OE] When was formed from the ancient interrogative base *qwo- (source also of English what, who, etc) and a nasal suffix which also appears in then. From the same ancestor, but with an additional dental suffix, came Latin quando ‘when’, source of English quandary. => quandary
when (adv.)
Old English hwænne, hwenne, hwonne, from Proto-Germanic *hwan- (cognates: Old Saxon hwan, Old Frisian hwenne, Middle Dutch wan, Old High German hwanne, German wann "when," wenn "if, whenever"), from pronominal stem *hwa-, from PIE interrogative base *kwo- (see who). Equivalent to Latin quom, cum. As a conjunction in late Old English. Say when "tell me when to stop pouring you this drink" is from 1889.
双语例句
1. The best thing to do when entering unknown territory is smile.
踏入未知地带最好的对策就是微笑。
来自美剧《凯莉日记》
2. When life gets hard and you want to give up, remember that life is full of ups and downs, and without the downs, the ups would mean nothing.
当生活很艰难，你想要放弃的时候，请记住，生活充满了起起落落，如果没有低谷，那站在高处也失去了意义。
来自
3. Good luck is when an opportunity comes along and you're prepared for it.
好运就是当机会来临时，你早已做好了准备。
来自金山词霸 每日一句
4. If you're lonely when you're alone, you're in bad company.--Jean Paul Sartre
如果你独处时感到寂寞，说明没有把自己陪好。
来自金山词霸 每日一句
5. The turning point in the process of growing up is when you discover the core of strength within you that survives all hurt.