"Leaves turning green" 用英语可以说成 "the leaves are turning green" 或 "the leaves are greening up".
这个表达的来源是源于植物学的术语，在春天，叶子从无色变成绿色，这个过程就被称为 "叶子变绿"。
例句：
The leaves on the trees are turning green. (树上的叶子在变绿。)
The grass is greening up as spring approaches. (随着春天的到来，草地也在变绿。)
The plants in my garden are showing signs of new growth as the leaves turn green. (我花园里的植物正在长新叶，叶子变绿。)