题目

补全对话 A: Are you OK, Helen? B:     1     It’s Friday and I have biology. A:     2    B: No, it’s boring. A:      3    B: Oh,     4     Because I like my history teacher. How about you, Ann? A:     5     B: Why? A: Because I think art can make our life more beautiful. A. I like history best. B. You like biology very much. C. No, I’m not. D. Yes, I’m OK. E. My favorite subject is art. F. So what’s your favorite subject? G. And you don’t like biology?如图，固定的导热气缸开口向下，缸内活塞封闭了一定质量的理想气体，活塞可自由移动且不漏气，活塞下挂了一个沙桶，沙桶装满沙子时，活塞静止，然后在沙桶底部钻了一个小洞，让细沙慢慢地漏出，设气缸外部的大气压强和温度恒定不变。则A.缸内气体压强减小B.缸内气体内能增加C.外界对缸内气体做功D.缸内气体放出热量