⏪ 新概念英语 - [4-029] - (97版) ⏩ ⏳ 正在检测本地文件... First listen and then answer the following question.先听录音，然后回答后面的问题。What is a hovercraft riding on when it is in motion? 气垫船在运动时骑在什么上面？The hovercraft 📁 请先导入本地文件， 需要帮助？点击我 ↗