北美洲的一种兰花，叶单生，花具有丝状反析花瓣。

North American orchid having a solitary leaf and flowers with threadlike petals.

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灰毛菊属的任何一种植物，产于欧洲南部，具有单生包片或银色的头状花序，管状花呈浅紫色。

Any plant of the genus xeranthemum native to southern europe having chaffy or silvery flower heads with purplish tubular flowers.

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脉叶十大功劳：一种十大功劳属常绿灌木，尤指冬青叶十大功劳，分布于北美洲的西北部，有带细锯齿单叶的复叶和开有蓝花的黑色果实。

Any of various evergreen shrubs of the genus Mahonia, especially M. aquifolium of northwest North America, having compound leaves with spiny-toothed leaflets and black berries with blue bloom.

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So, you might have noticed that we will have spent about 6 and 1/2 lectures just getting to the point where we have only one electron, so we're only up hydrogen so far.

你们可能已经注意到了,我们已经花了６周半的时间,来仅仅是讲到单电子问题的情形，我们现在只研究氢原子。

麻省理工公开课 - 化学原理课程节选