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问题 选择题

方程x2-3x+4=0的根的情况是（　　）

A．有一个实数根

B．有两个相等的实数根

C．没有实数根

D．有两个不相等的实数根

答案

∵a=1，b=-3，c=4，

∴△=b2-4ac=（-3）2-4×1×4=-7＜0，

∴方程没有实数根．

故选C．

改错题

短文改错

Dear Susan,

I am very glad to hear you are coming to visit me the next Friday. Unfortunate, I won’t be able to meet you at the airport since I have classes in afternoon. You won’t find difficult to get to the city center. The airport bus leaves every 30 minute and will take you rightly to the Friendship Hotel. My class will be over by then or I will pick you up there. I will take you together to a hot-pot restaurant for dinner and we’ll talk with our plan for the weekend over dinner. Having a pleasant trip and see you Friday.

Yours,

Zhang Ming
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单项选择题

老年男性，刺激性干咳2月余，多次痰查癌细胞阴性，胸片除右中肺叶局限性透亮度增加外，未见其他异常，最可能的诊断是（）

A.支气管结核

B.气管异物

C.早期肺癌

D.慢性支气管炎

E.急性支气管炎
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