一叶知秋

lit. the falling of one leaf heralds the coming of autumn (idiom) / fig. a small sign can indicate a great trend / a straw in the wind

one / single / a (article) / as soon as / entire; whole; all; throughout / "one" radical in Chinese characters (Kangxi radical 1) / also pr. [yao1] for greater clarity when spelling out numbers digit by digit

to be in harmony

leaf / page / lobe / (historical) period / classifier for small boats / a surname

to know / to be aware

autumn / fall / harvest time

old variant of 秋[qiu1]

see 鞦韆|秋千[qiu1 qian1]