根据对话意思和所给首字母，写出完整正确的单词。
Betty: Well, it's great to be here in Beijing.
Helen: Yes, it's exciting. Lots of 1. c______ take place every day.
Betty: And the Olympics are coming. I think Beijing is really the place to be right now.
Helen: Yes, 2. m______ people are curious about Beijing than before. They all want to see it themselves.
Betty: Beijing is really a great city. But there are also some problems, such as pollution and 3. c______ traffic.
Helen: You're right. There are a lot of challenges (挑战).
Betty: So our government has started "The Green Olympics Action Plan" to 4. b______ Beijing
into a better place to live in.
Helen; That sounds great. We all 5. h______ the Olympics will be a great success.