在四棱锥 P﹣ ABCD 中, 底面 ABCD 是矩形, PA⊥底面 ABCD, 且 PA=AB, AD = √3AB,则二面角 P﹣ CD﹣ B 的大小为()

在四棱锥 P﹣ ABCD 中, 底面 ABCD 是矩形, PA⊥底面 ABCD, 且 PA=AB, AD = √3AB,则二面角 P﹣ CD﹣ B 的大小为()

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I think the coffee beans are from Brazil, ________ I’m not completely sure.

I think the coffee beans are from Brazil, ________ I’m not completely sure.

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—Im afraid we cant work out the math problem________the teacher helps us.—Thats

—Im afraid we cant work out the math problem________the teacher helps us.—Thats true. Its too diffic

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—I think I am the shyest in my class. What should I do?—Be more active in class,

—I think I am the shyest in my class. What should I do?—Be more active in class, ________ you can im

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This morning I forgot to bring food. And it’s kind of you to share _____ with me

This morning I forgot to bring food. And it’s kind of you to share _____ with me.

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