People play it in the open air.
举一反三
- People can open it and let in light and air.
- 中国大学MOOC: Some people become （4） in winter, when the days are dark and most people spend less time in the open air.
- People eat dumplings and new-year cakes(). A: in the open air B: in their houses C: in the parks D: near their houses
- The pressure of pilot air is usually （） than that of starting air.
- 词汇与结构 Warm air is less dense than cool air, and _____ air is less dense than dry air.