You'll need to keep a clear head for your interview.

你面试时需要保持清醒的头脑。

《牛津词典》

One, sold as RU-21, is also known by the nickname “KGB”, because it was supposedly developed to help Russian spies keep a clear head while drinking.

其中一种以RU-21为名出售，它还有一个绰号叫“克格勃”。 因为据说它是为了帮助苏联间谍在饮酒时保持清醒而发明的。

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A study has found that the middle aged and elderly need just as much as the young if they want to keep a clear head the next day.

研究发现，中老年人和年轻人一样需要充足的睡眠，以使其在第二天保持清醒的头脑。

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He's no recluse, but he likes to spend time alone, roaming the mountains near his home in upstate Vermont, which helps keep his head clear.

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"I had to learn to take my time in judo, and I was just able to keep a clear head, " said Rousey, who became the first American woman to win an Olympic judo medal in Beijing.

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These are some of the other things that go sailing through my head as I strain to keep the car between the lines: Leaving the desert on a clear day.

NEWYORKER: Indianapolis (Highway 74)