甲步行每分钟行80米，乙骑自行车每分钟行200米，二人同时同地相背而行3分钟后，乙立即调头来追甲，再经过（　　）分钟乙可追上甲．

“陛下”本是对他人的尊称。“陛”是台阶，称人“陛下”表示谦卑，意思是我不敢直接靠近你，只能站在台阶下和你说话。但秦以后，“陛下”一词只能专称皇帝。这体现了皇帝制度的哪一特点（   ）

下列选项中不属于一对相对性状的是（　　）

阅读理解

    This is my new bedroom. There is a small shelf on the desk. Two end tables are near the bed and a photo is over the bed. The chair is in front of the desk. Look at my shoes. They are under the bed. I clean my bedroom on Sunday. I empty the trash every day. Mom says I'm a helpful boy.