The high notes were slightly flat.

这些高音略为偏低。

《牛津词典》

Eggs: long 0.5 mm, ovate, slightly flat, yellowish-white, hatch change before dark brown.

卵：长0.5毫米，卵形，稍扁、黄白色、孵化前变黑褐色。

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For example, a wine may fall short of the mark because a low level of acidity leaves it tasting slightly flat or a high level of tannin gives it an unpleasing bitterness.

例如，葡萄酒会因为酸低而口感平淡味短，或者因为丹宁高显得味苦。

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So even if the UK economy is only slightly less flat than a pancake, and the US and continental Europe aren't exactly booming, Asia, for example, is an altogether different and more buoyant economic world.

BBC: The bad and the good of bumper bosses pay

The company, which operates approximately 1, 860 retail jewelry stores in the U.S. and U.K., was led by the strength of U.S. operations, while its U.K. business sales were slightly down or flat, year-over-year.

FORBES: Signet Sales Up 10.7%, Same Store Sales Up 10.6%

Shares were flat to slightly higher after the company reported its second straight quarterly profit.

FORBES: After Hours: Netflix Shares Soar