I think 1likes dogs. Dogs are our friends. My friend Tomson likes dogs very2 . He has a big dog. 3name is Bobo. He's bright(聪明的). Every Saturday aftemoon Tomson takes Bobo for a long walk in the street. Sometimes Tomson takes Bobo to the park. Tomson4the frisby and Bobo catches it in the air. Bobo can open the door and close the door. When Tomson goes to school, Bobo stands in5of the door and waits6Tomson coming. When he sees Tomson, he7 the door and catches his bag. What a bright dog!

    I like Bobo. I often go to Tomson's home to play8 him. I often give Bobo  9  to eat. I want to have a dog, too.

如图，显微镜下观察到的物像在视野右下方，要把物像调到视野中央，应将玻片标本向什么方向移动（　　）

下列人物中，促使20世纪初的中国社会发生第一次历史巨变的是

探究：有一弦长6cm，宽4cm的矩形纸板，现要求以其一组对边中点所在直线为轴，旋转180°，得到一个圆柱，现可按照两种方案进行操作：

方案一：以较长的一组对边中点所在直线为轴旋转，如图①；

方案二：以较短的一组对边中点所在直线为轴旋转，如图②．

（1）请通过计算说明哪种方法构造的圆柱体积大；

（2）如果该矩形的长宽分别是5cm和3cm呢？请通过计算说明哪种方法构造的圆柱体积大；

（3）通过以上探究，你发现对于同一个矩形（不包括正方形），以其一组对边中点所在直线为轴旋转得到一个圆柱，怎样操作所得到的圆柱体积大（不必说明原因）？