今天，我发现姥姥家后山上树的’树叶都掉光了，只有松树的树叶还绿着。我带着问题去问妈妈。妈妈说：别的树叶是圆的，但松树叶象针一样细。圆形的树叶散发水分快，而松树的树叶散发水分慢，所以松树四季常青。今天我又学到了新的知识。
Today, I found that the leaves of the trees on the mountain behind grandma’s house were all gone, only the leaves of the pine trees were still green. I went to ask my mother with questions. Mother said: the other leaves are round, but the pine leaves are as thin as needles. The round leaves give off water quickly, while the pine leaves give off water slowly, so the pine is evergreen all the year round. Today I learned something new.