日批在线视频_内射毛片内射国产夫妻_亚洲三级小视频_在线观看亚洲大片短视频_女性向h片资源在线观看_亚洲最大网

文字稿:

After almost dying out in the 1970s, a kind of whistling language is now undergoing a revival.

Silbo Gomero, as it's known, has become a compulsory subject in one school in Spain's Canary Islands.

The whistling approximates the sounds of the Spanish language.

It can be heard from two miles away, and was used to communicate across valleys and ravines before the arrival of telephones.

Vocabulary 詞匯:

dying out 正在消失的

undergoing a revival 趨于重振

compulsory 必需的，強迫的

approximates 模仿，接近于

ravines 峽谷