企业在计划期内应当出产可供销售的产品和工业性劳务的价值称为（）A、总产值 B、商品产值

阅读理解。

     Tom lived in a town near New York. His father had a shop there and his mother was a doctor. He

was seven years old this year and began to go to school this September. It was a little far(远的) from

their shop and his father drove a car to take him to school five days a week. So he was never(从不)

late for class and his teachers likes him very much.

     It was Monday that day. Miss Green was teaching them to count(数数) from one to ten in the

morning. Tom was studying hard. Soon he could count them. Green was happy and asked, "How

many people are there in your family, Tom?"

     Tom stood up and said, "Two, Miss."

     "Who are they?"

     "My father and my mother."

     "Oh," Miss Green was surprised. She then said, "There’re three people in your family."

     "But now I’m not at home. I’m at school, you know!”

1. Where did Tom’s father work? _______.

A. In a factory.

B. In a school.

C. In a shop.

D. In a hospital.

2. Tom was now a student of_______.

A. Grade One

B. Grade Two

C. Grade Three

D. Grade Four

3. Tom was never late for school because_______.

A. all his teachers liked him

B. he went to school in a car

C. his house was next to the school

D. he just began to school a month ago

4. Miss Green taught her children to count from one to ten_______.

A. every day      

B. one Monday morning

C. in Tom’s house      

D. five days a week

5. Which is the best title(题目) for this story?_______.

A. Two or Three?      

B. From One to Ten

C. Tom and his family      

D. Miss Green and Her Students

已知二次函数y=x²-5x-6．

(1)求此函数图象的顶点A和其与x轴的交点B和C的坐标；

(2)求△ABC的面积．

水平传送带匀速运动，速度大小为v，现将一小工件轻轻地放在传送带上，它将在传送带上滑动一段距离后，速度才达到v，而与传送带相对静止．设小工件的质量为m，它与传送带间的动摩擦因数为μ，在m与皮带相对运动的过程中（    ）

A．工件是变加速运动

B．滑动摩擦力对工件做功mv²/2

C．工件相对传送带的位移大小为v²/（2µg）

D．工件与传送带因摩擦产生的内能为mv²/2

“生命链”中最重要的是哪一环？

如何选定单形符号？