Deciduous means that the trees' leaves turn different colors and fall off each year.

叶指树木的叶子会变成不同的颜色，并且每年都会凋。

In some tropical forests, the trees' leaves will fall off in the dry season just like deciduous forests.

热带森林中，树木的叶子旱季会像叶林样凋。

Just like the leaves falling every autumn, the trunks themselves return to the soil to feed the next generation.

就像是每年秋天凋的叶子，树干再回到土壤中继续养育下代。

Dead leaves floated on the surface of the water.

【surface】凋的树叶漂浮水面。

They are formed in the preceding year, a little while before the leaves begin to fall; and as they form, they loosen the old leaves, and soon push them off.

它们前年就已经形成，就是树叶凋之前的小段时间形成；它们形成后就会松开老叶子，然后将它们挤掉。