小明学习了热学知识后，知道水的比热容为4.2×103J/〔kg·℃〕，他想估算一下他家每天烧水、做饭需要的热量，于是小明仔细记录好家里每天烧水、做饭、炒菜需要的时间，并把它折算成烧水的时间，相当于每天将40kg、20℃的水烧到70℃。
小叶用激光灯对着光滑的大理石地面照射，无意中发现对面粗糙的墙壁上会出规一个明亮的光斑，而光滑地面上的光斑很暗，对此现象解释较合理的是( )
下列关于酸的含义说法正确的是( )
My name is Joe. I have two friends Bob and Paul. We play sports and eat lunch together every day. We like hamburgers for lunch.
Paul and I like French fries, but Bob doesn't. Bob and Paul like ice cream, but I don't. Paul has a great sports collection. He has 20 tennis rackets, 15 baseballs and 11 tennis. But he doesn't play soccer. Bob and I have a small sports collection. But we both have a soccer.
某人患有炎症，血液中含量会明显增加的成分是（ ）
A．此反应有单质生成
B．原子是不可分的
C．图中生成物全部是化合物
D．____
