车削圆柱形工件时，产生锥度缺陷与机床哪些因素有关。

下列工具中为需求分析常用工具的是( )。

A．PAD

B．PFD

C．N-S

D．DFD

典型借鉴：是指从他人(或对方)那里发现、学习并应用最佳做法的过程，以达到帮助改善自身业绩的目的。根据上述定义，下列属于典范借鉴的是( )。

A．甲村参考乙村因卖梨枣收入颇丰的做法，同样开始种植梨枣

B．考生甲某在同桌乙桌的帮助下，成绩大幅提高

C．甲厂吸取生产同产品的乙厂的经验，降低成本，提高效益

D．甲某看到乙某倒卖盗版光碟赚钱不少，也加入了此行列

阅读理解。

      Christmas was just a week away and I had five people left to shop for and only three dollars.

     "Let's set a price limit(限制)on our gifts this year," I suggested to my best friend Joanie.

     "That's a good idea,"Joanie agreed."How about nothing over five dollars?"

      "How about sixty cents?" I felt like the biggest cheapskate in the world.

     "I guess this is where I'm supposed to say it's not the gift but the thought that counts,"Joanie smiled.

     It is almost impossible to buy anything under sixty cents, so it was really going to have to be very small

gifts with very big thoughts.

     Finally, Christmas Day arrived. I gave my mother a candle with a note that said," You are the brightest

light in my life." She almost cried when she read the note.

     I gave my brother a wooden ruler. On the back of it I had painted,"No brother in the world could measure

up to (比得上) you." He gave me a bag of sugar and had written on it, " You ' re sweet."

     For Joanie, I painted a pair of shoes with a note that said, " No one could ever fill your shoes (代替你)."

She thanked me and said I always tickted (搔) her and made her laugh. 

     To my other two friends, I gave Annie a paper fan and a note on it,"I' m your biggest fan." I gave Helen a

calculator (计算器) that cost one dollar and I painted a message on the back,"You can always count on(依靠)

me." My mother knows she is the most important person in my life.

     My brother thinks I' m sweet. Joanie thinks I' m funny and make her laugh, which is important because her

dad moved away last year and she misses him and is sad sometimes.

1. When Christmas neared, the author worried that she _____.

A. had few friends to give her gifts

B. had little money to buy gifts for others

C. didn' t know what gifts her friends would like

D. didn' t have enough time to shop

2. The underlined word "cheapskate" in Paragraph 4 may mean a person who _____.

A. is the poorest in the world

B. buys the cheapest skateboards

C. spends as little money as possible

D. buys the cheapest things in the world

3.The author gave her mother a candle because it represents  _____.

A. her life

B. her mother' s life

C. her role in her mother' s life

D. her mother' s role in her life

4. What lesson can we learn from the passage?

A. It is an art to choose gifts.

B. It is the thought not the gift that matters.

C. How to choose cheap gifts.

D. Giving gifts improves friendships.

某研究性学习小组用图甲所示的装置探究加速度与合外力的关系，装置中的铝箱下端连接纸带，砂桶中可放置砂子以改变铝箱所受的外力大小。铝箱向上运动的加速度a可由打点计时器和纸带测出。现保持铝箱总质量m不变，逐渐增大砂桶和砂的总质量进行多次实验，得到多组a、F值（F为力传感器的示数，等于 悬挂滑轮绳子的拉力）。已知重力加速度为g，不计滑轮的重力。某同学根据实验数据画出了图乙所示的一条过坐标原点O的倾斜直线，其中纵轴为铝箱的加速度大小，横轴应为________________（用所给字母表示）；当砂桶和砂的总质量较大导致a 较大时，图线

A.偏向纵轴

B.偏向横轴

C.仍保持原方向不变

D.斜率逐渐减小

公司的基本义务有哪些？