过原点且与直线垂直的平面方程为______．

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问题填空题

过原点且与直线

垂直的平面方程为______．

答案

参考答案：2x+y-3z=0

解析：[解题指导] 本题考查的知识点为平面方程和平面与直线的关系．
由于已知直线与所求平面垂直，可知所给直线的方向向量s平行于所求平面的法向量n．由于s=(2，1，-3)，因此可取n=(2，1，-3)．由于平面过原点，由平面的点法式方程，可知所求平面方程为
2x+y-3z=0

阅读理解

阅读短文，判断下列句子正 ( T)误 ( F) 。

A woman comes into a bank with her son in her arms (抱着). The boy is only two years old.

He is eating a cake.

When the woman comes to one of the windows, the boy watches the teller (出纳员) carefully.

Then he gives his cake to the teller. The teller smiles and shakes (摇) his head.

"Oh, no, my dear. Don't do that. We aren't in the zoo," his mother says. Then she speaks to the

teller, "I'm sorry. Please forgive (原谅) my son. He has just been to the zoo."

( ) 1. The boy is three years old. He's eating a banana.

( ) 2. The teller watches the boy carefully and gives him a cake.

( ) 3. The woman and her son have just been to the zoo.

单项选择题 A1/A2型题

关于急性播散性脑脊髓炎下列哪项描述不正确（）。

A.是广泛累及脑和脊髓白质的急性炎症性脱髓鞘疾病

B.通常发生在感染后、出疹后或疫苗接种后

C.其病理特征为脱髓鞘病变常侵犯大脑半球或整个脑叶，病变多不对称，多以一侧枕叶为主

D.急性坏死性出血性脑脊髓炎又称为急性出血性白质脑炎

E.应与单纯疱疹病毒性脑炎和多发性硬化鉴别