对特定行政系统的战略性、长期性与全面性存在与运行产生根本性影响的各种环境因素集合，指

下列方程中，无论a取何值时，总是关于x的一元二次方程的是[ ]

A.（2a-1）（x²+3）=2x²-2

B.ax²-2x-9=0

C.ax²+x=x²-1

D.（a²+1）x+x=0

消化系统过敏反应出现的主要症状是（）。

A.腹痛

B.吞咽困难

C.大小便失禁

D.便血

E.喉头水肿

阅读短文，并按照题目要求用英语回答问题。

I’m a 34-year-old man, married, lived in a nice house, and have a successful career as an educational consultant. But my life was not always so great. I had a learning disability from an early age. I went to a special school where I got plenty of extra help. Still, I suffered the rest of my school days in public schools.

My life improved remarkably when I discovered art. The art world gave me a chance to express myself without words. I went to a workshop and gradually got good at making things with clay(黏土). Here I learned my first important lesson: disabled as I was in language. I could still be smart and well express myself with clay. And my confidence came along.

I got my next lesson from rock climbing. It was a fun thing but I was scared from the start. I soon noticed it wasn’t a talent thing; it was practice. So I did it more. After about five years of climbing, I found myself in Yosemite Valley on a big wall. I learned that if you fall in love with something and do it all the time, you will get better at it.

Later I decided to apply my previous experience to learning how to read and write. Every day I practiced reading and writing, which I used to avoid as much as possible. After two hard years, I was literate.

Having gone through the long process with art, rock climbing, and reading and writing, now I’ve got to a point in my life where I know I am smart enough to dive into an area that is totally unknown, hard, but interesting.

Why did art give the author confidence? (No more than 10 words)

患者男性，31岁，有静脉吸毒史，突然出现胸部剧烈刺痛，伴有呼吸困难及发绀，该患者的诊断是

A．肺癌
B．肺气肿
C．心绞痛
D．肺梗死
E．胸膜炎

当企业的财务杠杆系数等于1时，说明( )。

A．企业没有负债筹资
B．总杠杆系数大于1
C．税前利润最大
D．EPS最大