如图为生态系统的碳循环示意图，“甲﹣戊”表示生物成分“A﹣D”表示生理或化学反应过程，“→”表示碳的流动方向．请据图分析作答：
Swimming is my favorite sport.There is________like swimming as a means of keeping fit.
—You should do some housework ________________ you have grown up.
—OK, dad, I will.
读《别董大》，“黄云、白日、北风、雁、雪”这几种景物串起来勾画出了一幅 ____画面，其作用是衬托____。
