An opportunity like this comes once in a lifetime.
像这样的机会一生也许只会遇到一次。
We water the flowers once a week.
我们每周给花浇水一次。
We have to water this cactus once a month.
我们必须每月给仙人掌浇一次水。
Reputation is a treasure that, once lost, can never be won back.
名誉如同珍宝，一旦失去，再难获得。
I once had a dream, in which I saw rice plants as tall as sorghum.
我曾经做过一个梦，在梦里水稻和高粱一样高。
Her kind neighbors once helped her out when she was in big trouble.
她善良的邻居们曾经在她遇到大麻烦时帮助过她。
Gabriela Mistral was once an ordinary teacher in a small village school in Northern Chile.
加布里埃拉·米斯特拉尔曾经是智利北部一所乡村学校的普通教师。
The function of a public library was once described as "less a reservoir than a fountain".
公共图书馆的功能曾被描述为“与其说是水库，不如说是喷泉”。
Its flattened shape implies that Iapetus once spun very quickly, completing a rotation in 16 hours.
它扁平的形状意味着土卫八曾经旋转得非常快，完成一次自转需要16个小时。
All jazz lovers should come to the Montreal International Jazz Festival at least once in a lifetime.
所有的爵士爱好者一生中都应该至少来一次蒙特利尔国际爵士音乐节。
This diary, which once had over 500,000 words, would eventually become The Travel Notes of Xu Xiake.
这篇曾经有着50多万字的日记，最终成为了《徐霞客游记》。
The salt and gypsum, the faunal changes, and the unusual gravel provided abundant evidence that the Mediterranean was once a desert.
盐和石膏、动物群落的变化和不寻常的沙砾充分证明地中海曾经是一片沙漠。
Noble Laureate and physiologist Albert Szent-Gyorgyi once described discovery as "seeing what everybody has seen and thinking what nobody has thought".
诺贝尔奖得主、生理学家阿尔伯特·森特-乔吉曾将发现描述为“看到所有人看到的，思考没有人想到的”。
It made a refreshing change to be taken seriously for once.
总算有一次受到认真对待，这变化真是令人耳目一新。
The spirit of adventure rose in the boys' souls once more.
冒险精神再次在孩子们的心中油然而生。
大门立时洞开。
我们马上出发吧！
It is once again the 7-day National Day holiday.
又到7天国庆长假了！
One hot summer afternoon, he was taking a walk when a thunderstorm started all at once.
一个炎热的夏日下午，他正在散步，突然下起了雷雨。
Perhaps I may be able once more to see the round red sun before he entirely disappears.
也许在圆圆的红日完全消失之前，我还能再看到它一眼。
This contributed to the deterioration of the company's once-spirited culture, which had motivated employees to take risks and make miracles.
这一做法有损公司原本生机勃勃的企业文化，而正是这种文化激励员工敢于冒险、创造奇迹。
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