This summer I will leave the junior high school where I have been for three years. I am generally considered to be a careful and polite boy now. However, five years ago, I was a little bit bossy(专横的). I often fought with other boys and sometimes I even fought with my elder sister. When I saw Superman on TV for the first time, I dreamed of being a superman one day.
    One P.E. class, I called up all of my friends to get together in our classroom. “Can anybody jump out of the window?” I asked them. After hearing this, all my friends kept silent. “I know you are all chickens,” I said. “Can you?” one of my friends asked me. “Sure!” I answered. “If I do it, I will get all the toys that you have. If I fail, you will get all of my toys, OK?” They said, “OK!”
Then I went up to the window of the second floor. I took a deep breath and then jumped down, stretching out my arms just like Superman. Then I hit the ground.
     When I opened my eyes, I found myself lying in the hospital. I was taken to the hospital because my arms were badly hurt. Later, I heard that my P.E. teacher nearly lost his job for this, but I never received the serious punishment I feared.

铜仁市地处武陵山区，石灰石资源丰富，某课外小组同学取该样品12.0g于烧杯中，向盛有样品的烧杯中加入足量一定溶质质量分数的稀盐酸溶液充分反应，所用稀盐酸质量（用X表示）和烧杯中剩余固体质量（用Y表示）如图所示（石灰石的主要成分是碳酸钙，杂质不溶于水也不与酸反应），请回答下列问题：

（1）石灰石中碳酸钙的质量是多少？

（2）充分反应后共生成多少二氧化碳？

（3）所用稀盐酸的溶质质量分数是多少？

抛物线y＝x²－4x－7的顶点坐标是(   )

芽能通过细胞的生长、分裂和分化发育成枝条，主要是因为芽中有（   ）

Brian：Hi, Cindy.____

Cindy：Hi, Brian. It is nice to see you and so many old classmates.

Brian：So it is.____

Cindy：You're right.  It's really a long time.

Brian：Did you see the old photos on the wall?

Cindy：I sure did.____

Brian：But those are some great memories.

Cindy：Hey ！____

Brian：Yes, it is. I remember he used to stay up all night studying.

Cindy：____

Brian：Yes. He was the only one left in the class when he woke up.

Cindy：That was really funny.

A. And then he would fall asleep in class.

B. Long time no see!

C. Who took these photos?

D. Isn't that John over there?

E. We looked so funny in them.

F.I can't believe it's been ten years.

G. Did he use to be short ?