如图所示，足够长平行金属导轨倾斜放置，倾角为37°，宽度为0.5 m，电阻忽略不计，其上端接一小灯泡，电阻为1 Ω.一导体棒MN垂直于导轨放置，质量为0.2 kg，接入电路的电阻为1 Ω，两端与导轨接触良好，与导轨间的动摩擦因数为0.5.在导轨间存在着垂直于导轨平面的匀强磁场，磁感应强度为0.8 T．将导体棒MN由静止释放，运动一段时间后，小灯泡稳定发光，此后导体棒MN的运动速度以及小灯泡消耗的电功率分别为(重力加速度g取10 m/s²，sin 37°＝0.6)(  )

下列有关等浓度双氧水分解的图象中，a为加二氧化锰，b为不加二氧化锰，一定正确的是（   ）

在甲、乙、丙、丁四个培养皿中分别放等量的棉花，再将相同数量（各100粒）的绿豆种子放在上面，在不同条件下进行培养，数日后记录种子萌发情况如表

装置	甲	乙	丙	丁
温度	23℃
光照情况	日光下		黑暗中
棉花干湿状态	潮湿	干燥	潮湿	干燥
种子萌发粒数	92	0	93	0

（1）根据本实验，可得出的结论是：种子萌发需要____

（2）要证明“光照的有无对绿豆种子的萌发是否有影响”，在实验设计上可选用____ 两组作对照，根据这组对照实验的现象你得出的结论是____ 

人体由八大系统组成，有些器官属于甲系统，也属于乙系统；而有些器官则只属于甲系统而不属于乙系统．据此判断，下列哪种器官不同于其他三种器官？（ ）

       One day Daddy and I went out    1    a walk. On the way we   2   a lot of people. We went up and   3  a look. Oh, dear!   4  did we see? There   5  a donkey(驴) in the middle of the road. It would not move. The cars and buses could not get 6  .
Then a policeman came. " 7  donkey is this?" he asked. "It' s   8   ," said a farmer, "but I   9  move it. " The policeman and the farmer did 10 best to move the donkey, but it would not move. We laughed, but the  11   of the cars and the buses were   12   . "We can't move the donkey," the farmer and the policeman said. "What shall we do?"
"Give him a carrot," my father said.
"   13 a good idea!" said the farmer.
Soon he found a   14 and showed it to the donkey. When the donkey saw a carrot, it jumped up and walked after the farmer.  15   the cars and buses could get past at last.