给出下列命题：
①若a，b，c分别是方程x + log3x = 3，x + log4x = 3和x + log3x = 1的解，则a＞b＞c；
②定义域为R的奇函数f（x）满足 f（3 + x）+ f（1 - x）= 2，则f（2010）= 2010；
③方程2sinθ = cosθ在 [0，2π）上有2个根；
④已知Sn是等差数列{an}（n∈N*）的前n项和，若S7＞S5，则S9＞S3；
其中真命题的序号是
．③④
| 综合填空，选择所给单词并用其适当形式填空。 | |
manners. It's 1______ to follow them. When you sit down at the table, take your napkin and 2______ it on your lap. The dinner always 3______ with a small dish. When you start eating, you should keep the fork in your 4______ hand. It's polite to finish 5______ everything on your plate, so don't take 6______ food than you need. Maybe you don't know whether it's polite or not to speak loudly at the table. The answer is that you should speak 7______ and smile a lot. When you drink to 8______, you'd better raise your glass and take only a sip. Remember not 9______ too much. If you can't remember these 10______. Just do as other people do. |