⏪ 新概念英语 - [4-030] - (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。How did people probably imagine the sea-floor before it was investigated? 在海底被勘探之前，人们可能如何想象海底？Exploring the sea-floor 📁 请先导入本地文件， 需要帮助？点击我 ↗