leaf|leaves

我在三明治上加了一片新鲜的生菜叶。

I added a fresh lettuce ___leaf to my sandwich.

到十一月初，天气变冷，树木开始落叶。

By early November it’s getting cold and the trees are starting to lose their ___leaves.

绿色的叶子长在树上。

Green ___leaves grow on the tree.