It's sunny today. The sun is shining(照耀)in the sky and it's very hot. Nancy goes to the train station(车站)to meet her mother at noon. She walks in the street. There are no trees and she's fat. So she feels very hot. But she doesn't find (发现)a boy walking behind her. And she meets a friend and says "Hello" to him. "Who's the boy behind you?" asks(问) the man. Now she sees the boy. She is angry and asks, "Why(为什么) do you walk behind me, boy?" there's no shade(阴凉处) in the street, you know" answers the boy. "It's cool behind you, I think(想)."

—Is the cola yours　　　Ann's?

—It's Ann's.

在KClO₃分解制O₂的反应中MnO₂作催化剂，下列有关催化剂说法不正确的是(    )

“雪龙”号是中国最大的极地考察船，也是中国唯一能在极地破冰前行的船只．雪龙船耐寒，能以1.5节航速连续冲破1.2米厚的冰层（含0.2米雪）．满载时的排水量为21025吨，自重15000吨．“雪龙”号上的装备也是经常更新换代．下面我们一起来领略下“雪龙”号上的先进设备．1架“雪鹰”号直升机、1艘黄河艇、一艘无人智能测量艇﹣“海巡166﹣01”艇、固定翼飞行机器人、旋翼飞行机器人和冰盖漫游机器人（图为冰盖漫游机器人）3员“大将”组成的机器人兵团、以及多波束声呐、卫星实时动态差分定位系统、磁力仪器等扫测设备，这些设备为“雪龙”号顺利完成极地科考任务保驾护航．

（1）冰盖漫游机器人的四个轮子用四个三角形履带替代，是为了____ 对冰面的压强．

（2）“雪龙”号的最大载重量为____ 吨．

（3）声纳是利用____ 反射来完成定位．