根据图回答下列问题：
点P从点O出发，按逆时针方向沿周长为l的图形运动一周，O，P两点间的距离y与点P走过的路程x的函数关系如图，那么点P所走的图形是（ ）
Tom hasn't appeared for 10 days. So I promise his parents: “I'll report back, the moment I ________ him.”
读如图所示的“地壳物质循环简略示意图”，完成下列问题：
