It's a milestone in history.

这是一个历史里程碑。

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He said the launch of the party represented a milestone in Zambian history.

他说该党的成立代表着赞比亚历史上的一个里程碑。

《柯林斯英汉双解大词典》

Andrew Hamilton, Oxford's vice-chancellor, said: "the school represents a huge milestone in oxford's history."

牛津大学副校长安德鲁·汉密尔顿表示：“这所学校是牛津历史上的一座巨大里程碑。“

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If that is done, Camp David will be regarded as a great milestone in history.

CENTERFORSECURITYPOLICY: Camp David: Finality Guaranteed by the world

The recipient lived just eighteen days, but the feat was a milestone in the history of medicine.

NEWYORKER: The Operator

The Solar Impulse considered the world's most-advanced sun-powered plane set down about 12:30 a.m. at Sky Harbor Airport, completing part of a journey that its pilot described as a "milestone" in aviation history.

WSJ: Solar plane lands in Ariz., 1st leg of major trip