某人沿水平方向用20N的力拉着一重为50N的箱子匀速向西运动，箱子受到的阻力大小是____ N，方向是____.用水平推力推停在地面上的汽车，但没有推动，这时推力____汽车所受到的阻力（选填“大于”，“小于”或“等于”）.

阅读理解

    Mr. Smith made many tests with different animals. They found that the monkey was the cleverest of all the animals. One day Mr. Smith put a monkey in a room. He also put some small boxes in it. In one of the boxes there was some food. “How long will it take the monkey to find the food?” Mr. Smith said to himself. “Let me wait and see.” He left the room and waited outside. Three minutes later, he put his eye to the keyhole (猫眼). What did he see? He saw the eye of the monkey. The monkey was on the other side of the door and looked at Mr. Smith through the keyhole.

某校组织班班有歌声比赛，8个评委为某个班级打出的分数如茎叶图所示，则这些数据的中位数是（　　）

填空题

 战 役             人物          成 语

①桂陵之战____  ____   姬发         围魏救赵

②牧野之战____ ____    晋文公       阵前倒戈

③城濮大战____ ____    孙膑         退避三舍

④长平之战____ ____    赵括         纸上谈兵