Close to the grottos, there is a cinema inside a deserted railway tunnel. 洞穴的附近有一個(gè)廢棄的鐵路隧道，里面設有電影院。
It is shown that an electrified railway tunnel is an effective channel for transmission of language and slow digital signals. 研究表明，電氣化鐵路隧道是語(yǔ)音和低速數字信號傳輸的有效信道。
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