石灰石是许多化工生产的原料之一，但制取下列物质不需要到石灰石的是（  ）

下列说法摘自某些刊物，你认为无科学性错误的是：

在“观察水的沸腾”的实验中，小明观察到水沸腾前和沸腾时水中气泡的上升情况不同，如图中a、b所示．则

阅读理解

B

    Last Friday, I agreed to meet some friends at 6：00 p．m．in a coffee shop．The weather was sunny, so I decided to walk there．I arrived ten minutes early．I ordered a cup of coffee and sat watching people．There were some boys playing football on the street，and a small boy was running after the ball as it rolled (滚)across the road．

    Suddenly(突然)，there came a car．It was going very fast．When the driver saw the boy in his way, he braked(刹车)hard．But it was too late…The small boy was lying on the street without moving．To everyone's surprise，the car didn't stop．It drove away quickly．

    People ran to the boy．There was a cut on the boy's head and he lost a lot of blood．The coffee shop owner (主人)telephoned the police．Soon an ambulance (救护车)arrived and took the boy to the hospital．

    At 6：30 p．m., the police arrived and started questioning people．About half an hour later, they asked me to go to the police station because I saw everything．I gave them all the information I knew because I really wanted them to catch the driver．I didn't leave the police station until 8：00 p. m．After that I went home because I didn’t feel like talking to anyone．

    The next day, the boy's parents called me to say thanks．They also told me their boy was fine and the driver was in the police station now．

阅读短文，选择正确的答案。
    A little mouse thought he was the tallest and strongest animal in the world. His mother said to him, "Don't say that in front of an elephant. He doesn't like that." The little mouse didn't listen to his mother. He went out to look for the elephant, but he didn't know who the elephant was. He asked an ant(蚂蚁) first, "Are you an elephant?" "No, I'm not," said the ant. "An elephant is much bigger than I am." Suddenly(突然), he saw four big trees. "Let me climb up(爬上) a tree. Then I can see where the elephant is," said the little mouse. "Get down! Get down!" someone shouted(喊) to him. "I'm the elephant. Go and climb that tall tree nearby. Then you can see me." "Now, I see. The elephant is the tallest and strongest animal in the world," said the little mouse.