这就是那家公司的股票价格一直保持得这么好的首要原因。

That's the primary reason the company's share price has held up so well.

《柯林斯英汉双解大词典》

事故仍然是美国人非自然死亡的首要原因。

Accidents are still the number one cause of premature death for Americans.

《柯林斯英汉双解大词典》

说到底，在这一方面由学生自主选择就是导致问题出现的首要原因。

After all, students making their own choices in this respect is what caused the problem in the first place.

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Now the number one reason, and we have to acknowledge it up front, is usually economically there's no alternative or people believe there's no alternative.

首要原因，我们必须承认，通常是因为，经济上没有其他选择,或者人们认为别无选择。

耶鲁公开课 - 心理学导论课程节选