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A sound made by tapping on the hull of a ship will be reflected from the sea bottom,

敲打船體所發了的聲音會從海底傳回來，

On the occasions when they have pushed to shore an unconscious human being they have much more likely done it out of curiosity or for sport, as in riding the bow waves of a ship.

當它們偶爾把一個失去知覺的人推到岸邊時，更大的可能是出于好奇或游戲，就像它們追逐被船首犁開的浪花一樣。

and yet one might be cautious about believing this statement.

不過，人們不會輕信她的抱怨。

The continents form rugged tablelands which stand nearly three miles above the floor of the open ocean.

大陸是崎嶇不平的高地，高出遼闊海洋海底近三英里。

He was, above all, a man who experimented:

他首先是個實驗工作者，

a wave length (the horizontal distance between two wave crests),

波長（兩個浪峰間的水平距離）