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and by measuring the time interval between the taps and the receipt of the echoes, the depth of the sea at that point can be calculated.

測出回聲間隔的時間，便可算出該處海洋的深度。

The shape and dimensions of the skyscrapers depend entirely on the necessity of obtaining the maximum income per square foot of ground,

每平方英尺地皮取得最大收入

and his hero was firmly rooted in his memories and experiences, and in both the history and the mythology of the vanished frontier.

他塑造的英雄人物深深地扎根于他本人的記憶和經歷之中，也扎根于有關已經消失的拓荒生活的歷史和神話之中。

sank with all flags flying----in the harbour of the birth.

帶著全身飄揚的彩旗，沉沒在了它誕生的港口。

His telescopic observations are justly immortal;

伽利略用望遠鏡所作的觀察確實是不朽的，

Such extreme cases must probably be taken with a grain of salt,

這種極端的事例雖不可全信，