A:“破镜难重圆”是因为固体分子间只存在着斥力
B:松软的大馍用手一捏体积会大大缩小,这说明分子间存在间隙
C:在空调房间吸烟时,会看到烟雾在空中弥漫,这是分子的无规则运动
D:用热水相比较冷水更容易去掉衣物上污渍说明温度越高分子的无规则运动越剧烈
用反证法证明命题“三角形中必有一个内角小于或等于60°”时,首先应该假设这个三角形中( )
回答问题:
“大河有水小河满,大河无水小河干。”这一谚语说明( )
阅读短文,判断正误。
It was Saturday yesterday. It was sunny. Li Lei helped his mother do the housework in the morning. He went to the park with his friends in the afternoon. They played football in the park. His sister Li Mei played computer games at home. Their father, Mr. Li, watched TV at home.
点A为数轴上的表示-2的动点,当点A沿数轴移动4个单位长度到点B时,点B所表示的有理数为( )