如图, 已知 AB 是圆柱底面圆的一条直径, OP 是圆柱的一条母线, C 为底面圆上一点,且 AC∥OB, OP = AB = √2OA, 则直线 PC 与平

如图, 已知 AB 是圆柱底面圆的一条直径, OP 是圆柱的一条母线, C 为底面圆上一点,且 AC∥OB, OP = AB = √2OA, 则直线 PC 与平面 PAB 所成角的正弦值为()

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Most students are playing on the playground and there are still ____ students st

Most students are playing on the playground and there are still ____ students staying in the classro

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—Can you speak Chinese, Steve?—Yes, only ____. I have been in China for only one

—Can you speak Chinese, Steve?—Yes, only ____. I have been in China for only one month.

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A year has four seasons and it ______ twelve star signs.

A year has four seasons and it ______ twelve star signs.

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某中学组织一支“雏鹰” 志愿者服务队, 带领同学们利用周末的时间深入居民小区开展一些社会公益活动. 现从参加了环境保护和社会援助这两项社会公益活动的志愿者中,

某中学组织一支“雏鹰” 志愿者服务队, 带领同学们利用周末的时间深入居民小区开展一些社会公益活动. 现从参加了环境保护和社会援助这两项社会公益活动的志愿者中, 随机抽取男生 80 人, 女生 120

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