一定条件下，在体积为10 L的密闭容器中，1 mol X和1 mol Y进行反应：2X(g)＋Y(g)Z(g)，经60 s达到平衡，生成0.3 mol Z，下列说法正确的是（  ）

根据对话内容，从下面方框中选择适当的单词或词组填空，使对话内容完整正确。
medicine,      started,      terrible,      often,      wrong   
B: Bob                  D: Doctor
D: Come and sit down, Bob. What’s ____ with you?
B: I have a ____  pain in my stomach, doctor.
D: I see. When did it start?
B: It ____  yesterday. I didn’t want to eat anything. I’m not feeling well now.
D: Let me see, er, you have a fever.
B: I’ve got a headache, too. And my throat hurts.
D: Well, you’ve caught a bad cold.
B: I know these days the H7N9 flue is very popular. Is it serious?
D: No, not very serious, your temperature isn’t very high. Pay attention to your food and remember to wash your hands before meals. And you must stay in bed for 2 or 3 days and take the Chinese ____ .
B: How____ should I take it?
D: Three times a day after meals.
B: Thank you.

孙中山领导辛亥革命的指导思想是（   ）

已知抛物线y=ax²+bx+c的开口向下,顶点坐标为（2，-3）,那么该抛物线有（  ）

知识提纲能够有效地帮助我们记忆、理解历史知识。下图是某同学在整理课堂笔记后提炼出的部分要点。据此判断，他正在学习的主题是（   ）