中国社会学社

有50个同学，头上分别戴有编号1，2，3，…，49，50的帽子．他们按编号从小到大的顺序，顺时针方向围成一圈做游戏：从1号开始按顺时针方向“1，2，1，2…”报数，报到奇数的同学退出圈子，一圈下来后，接着又从编号最小的人重新开始“1，2，1，2，…”报数，报到奇数的同学退出圈子，经过了若干轮后，圆圈上只剩下了一个人，那么，这位同学原来的编号是______．

如图所示，从地面上方D点沿相同方向水平抛出的三个小球分别击中对面墙上的A、B、C三点，图中0点与D点在同一水平线上，知O、A、B、C四点在同一竖直线上，且OA=AB=BC，三球的水平速度之比为v_A：v_B：v_C=______．

计算2a-a，正确的结果是（　　）

A．-2a³

B．1

C．2

D．a

义齿主要为黏膜支持式，应考虑（）

A.基托蜡型适当加大

B.基托蜡型适当减小

C.不需要制作唇侧基托

D.基托蜡型适当变薄

E.基托蜡型适当加厚

阅读理解。

     When Father's Day comes from around, I think first of my stepfather. Don't get me wrong. I loved my

biological dad, but he wasn't much of a father to me. It's more like Daddy was his name than what he did.

     My stepfather is the best kind of dad. He took us fishing,and when I proved too impatient with a fishing

pole, hooking trees, people on the banks...anything but fishing, he patiently taught me to use a cane pole. His

patience eventually taught me patience. He took us camping, hiking and swimming, too; along the way he

taught us about the plants, animals and out of the way places we were discovering. I discovered peace in

nature, too.

     The beach was a favorite destination. I remember my stepfather cooking hot dogs and beans on a little

camp stove, often in a sudden shower, always avoiding sand that spread as I ran back and forth. He also

took us to the circus, and I got to ride an elephant and it interested me a lot. We went to Disney World a lot,

often camping in the park. And one year we took an unforgettable five-week trip from Florida to Wyoming,

across the upper states to Indiana, and back down to Florida. He played with us, too, and told us stories. On

summer evenings when I'd been running barefoot all day and he'd patiently dig out the splinters (刺) from my

feet, I knew I was loved.

     My stepfather led me to my future husband at my wedding. I insisted I was not nervous as I held his arm

so tightly that my nails left marks. In a few years, he became the best Grandpa imaginable to our three boys-

taking them fishing and camping, fixing them special foods, teasing them…

     My stepfather has plenty of interests of his own. He enjoys fishing and camping, he is good at math, and

he is a wonderful gardener and photographer. But he has always taken time to care for his family-even his

instant family-and that's why I say my stepfather is the best possible Real Dad.

1. The author's stepfather took her to do all of the following EXCEPT _____.

A. camping, hiking and swimming

B. going to the circus

C. traveling from Florida to Wyoming

D. planting in the park

2. Which of the following description is NOT given about the author's stepfather?

A. Patient

B. Kind

C. Honest

D. Clever

3. The author left marks on her stepfather's arm because she was _____.

A. disappointed

B. calm

C. tense

D. sad