Crab
词形变化
Crabs
复数
Crabs
the Crab
释义与例句
n.
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1.
A unit for measuring the intensity of astrophysical X-ray sources, defined as the intensity of the Crab Nebula at the corresponding X-ray photon energy.
name
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1.
The constellation and zodiacal sign Cancer.
天文 宗教 哲学