Correct
一叶知秋
/ yī yè zhī qiū /
Strokes
Definition
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
Example
Definition
the falling of one leaf is enough to tell of autumn's arrival—a straw shows which way the wind blows; a small sign can indicate a great trend