教学过程的实质即（）A、师生之间的互动 B、特殊的认识活动 C、促进学生身心发展的过

患者颏部跌伤，耳前区疼痛肿胀，前牙开后牙早接触，正确的诊断是()

A．下颌骨正中骨折

B．下颌角骨折

C．下颌骨颏孔区骨折

D．下颌升支骨折

E．下颌骨髁突颈骨折

已知关于x的方程x²+2（k-3）x+k²=0有两个实数根x₁、x₂．

（1）求k的取值范围；

（2）若|x₁+x₂-9|=x₁x₂，求k的值．

把下面的句子翻译成中文。

1. I have three new teachers.

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2. Who are they?

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3. Her class is so much fun.

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4. She's young and pretty. She's a university student.

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5. Do you have new teachers?

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6. He's from Canada.

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7. Who's that young lady?

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8.4除以2.1的商加上9.35。和是多少？

数学课本的面是长方形。  [ ]