下面哪项不属于油料作物？（） A.蓖麻 B.棉籽 C.亚麻籽 D.小麦

某同学设计了如图所示的装置，利用米尺、轻绳、轻滑轮、轨道、滑块、光电门、托盘天平和砝码等器材来测定滑块和轨道间的动摩擦因数μ。导轨上A处有一质量为M的滑块，滑块上装有宽度为b的遮光片，滑块和托盘上分别放有若干砝码，滑块上砝码总质量为m′，托盘和盘中砝码的总质量为m。导轨上B处有一光电门，可以测出遮光片经过光电门时的挡光时间Δt。实验中，滑块在水平轨道上从A到B做初速为零的匀加速直线运动，重力加速度g取10m／s²。

小题1:若测得AB距离为x，则计算滑块加速度a的运动学公式是 ▲  ；

小题2:根据牛顿运动定律得到a与m的关系为：，他想通过多次改变m，测出相应的a值，并利用上式来计算。若要求保证a是m的一次函数，必须使保持不变，实验中应如何操作？ ▲  ；

小题3:实验得到a与m的关系如下表所示，作出a—m图像，并根据图像求得μ=  ▲ （取两位有效数字）

顺序存储的表中有90000个元素，已按关键字值升序排列，假设对每个元素进行查找的概率相同，且每个元素的关键字值皆不相同，用顺序查找法查找时，需平均比较的次数为( )

A．25000

B．30000

C．45000

D．90000

根据短文内容，从短文后的选项中选出能填入空白处的最佳选项，选项中有两项为多余选项。

     I was ten when I first sat with my grandmother behind the cashier(收银台)in her general store.  1   I

quickly learned the importance of treating customers politely and saying "thank you."

     At first I was paid in candy.    2   I worked every day after school, and during the summer and on weekends and holidays from 8 a.m. to 7 p.m. My father helped me set up a bank account.  3   

     By the time I was 12, My grandmother thought I had done such a good job that she promoted me to

selling cosmetics(化妆品). I developed the ability to look customers directly in the eye. Even though I was just a kid, women would ask me such things as " What color do you think I should wear?" I took a real

interest in their questions and was able to translate what they wanted into makeup(化妆)ideas.   4   

     The job taught me a valuable lesson: to be a successful salesperson, you didn't need to be a Rocket

scientist-you needed to be a great listener.   5   Except they are no longer women purchasing cosmetics

from me; instead, they are kids who tell me which toys they would like to see designed and developed.

A.Later I received 50 cents an hour.

B.Before long, she let me sit there by myself.

C.I ended my selling a record amount of cosmetics.

D.Today I still carry that lesson with me: I listen to customers.

E.My grandma's trust taught me how to handle responsibility.

F.Soon I found myself looking more beautiful than ever before.

G.Watching my money grow was more rewarding than anything I could have bought.

金融危机爆发以来，中国政府积极参加20国集团的活动，呼吁“通力合作、共度时艰”。这表明[ ]

①中国政府积极参与国际合作，共同应对危机②当今时代的主题发生了变化③各国享有平等参与国际事务的权利④国家之间的共同利益是国际合作的基础

A．①②

B．①③

C．①④

D．③④

支行因验资（或增资）业务为客户出具询证函时按每份200元的标准收取手续费。（）