- 56natural resources自然资源 (0篇回复)
- 55natural disasters自然灾害 (0篇回复)
- 52the environment环境 (0篇回复)
- 51the weather天气 (0篇回复)
- 50social problems社会问题 (0篇回复)
- 49politics政治 (0篇回复)
- 48war战争 (0篇回复)
- 047the countryside乡村 (0篇回复)
- 046cities城市 (0篇回复)
- 045countries国家 (0篇回复)
- 042the internet and email网络与电子邮件 (1篇回复)
- 041computer电脑 (0篇回复)
- 040chatting online网络聊天 (1篇回复)
- 039fans and their idols影迷和他们的偶像 (0篇回复)
- 038show biz演艺界 (0篇回复)
- 037 science (0篇回复)
- 036history历史 (0篇回复)
- 035music音乐 (0篇回复)
- 034languages语言 (0篇回复)
- 033doing business做生意 (0篇回复)