Today young people learn variations of disco dancing so complex that it would take hundreds of hours of observation to articulate the motions . 现在年轻人学各种各样复杂的迪斯科舞，可能要花几百小时观察，才能把这些动作连贯起来。
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Observations : trainees are required to do 9 hours of observations of experienced teachers in the classroom 观察：受训者需要观察8小时的富经验的教师授课。
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The map was derived from nearly a thousand hours of observations of 575 overlapping patches of sky with the hubble space telescope ' s high - resolution cameras 图像来自于近千小时的观测资料，哈勃高精度望远镜拍摄的575副交迭图像。
