问题 单项选择题 B型题

普萘洛尔治疗心绞痛()

A.抑制心肌收缩力,减慢心率,降低心肌耗氧量

B.阻断血管平滑肌上的α受体

C.扩张外周小动脉,减轻心脏后负荷

D.对抗肾上腺素的升压作用

E.激动M受体下列药物临床应用的主要机制是

答案

参考答案:A

解析:酚妥拉明可扩张血管,降低外周血管阻力,使心脏后负荷明显降低,左心室舒张末期压与肺动脉压下降,心搏出量增加,心力衰竭得以减轻。由于酚妥拉明可直接舒张血管,大剂量阻断α受体,可用于去甲肾上腺素外漏,对抗其强大的收缩局部血管作用,防止组织坏死。酚妥拉明有"肾上腺素作用的翻转"作用,故可用于肾上腺髓质嗜铬细胞瘤的诊断。普萘洛尔可阻断心脏上β受体,抑制心肌收缩力,减慢心率,降低心肌耗氧量,用于治疗心绞痛。

阅读理解

阅读理解。

     A year after graduation, I was offered a position teaching a writing class. Teaching was a profession

I had never seriously considered, though several of my stories had been published. I accepted the job

without hesitation, as it would allow me to wear a tie and go by the name of Mr. Davis. My father went

by the same name, and I liked to imagine people getting the two of us confused. "Wait a minute" someone

might say, "are you talking about Mr. Davis the retired man, or Mr. Davis the respectable scholar?"

     The position was offered at the last minute, and I was given two weeks to prepare, a period I spent

searching for briefcase (公文包) and standing before my full-length mirror, repeating the words, "Hello,

class. I'm Mr. Davis." Sometimes I would give myself an aggressive voice. Sometimes I would sound

experienced. But when the day eventually came, my nerves kicked in and the true Mr. Davis was there.

I sounded not like a thoughtful professor, but rather a 12-year-old boy.

     I arrived in the classroom with paper cards designed in the shape of maple leaves. I had cut them

myself out of orange construction paper. I saw nine students along a long table. I handed out the cards,

and the students wrote down their names and fastened them to their breast pockets as I required.

     "All right then," I said. "Okey, here we go." Then I opened my briefcase and realized that I had never

thought beyond this moment. I had been thinking that the students would be the first to talk, offering their

thoughts and opinions on the events of the day. I had imagined that I would sit at the edge of the desk,

overlooking a forests of hands. Every student would yell. "Calm down, you'll all get your turn. One at a

time, one at a time!"

     A terrible silence ruled the room, and seeing no other opinions. I inspected the students to pull out their

notebooks and write a brief essay related to the theme of deep disappointment.

1. The author took the job to teach writing because _____.

A. he wanted to be expected

B. he had written some storied

C. he wanted to please his father

D. he had dreamed of being a teacher

2. What can we learn about the author from Paragraph 2?

A. He would be aggressive in his first class.

B. He was well-prepared for his first class.

C. He got nervous upon the arrival of his first class.

D. He waited long for the arrival of his first class.

3. Before he started his class, the author asked the students to _____.

A. write down their suggestions on the paper cards

B. cut maple leaves out of the construction paper

C. cut some cards out of the construction paper

D. write down their names on the paper cards

4. What did the students do when the author started his class?

A. They began to talk.

B. They stayed silent.

C. They raised their hands.

D. They shouted to be heard.

5. The author chose the composition topic probably because _____.

A. he got disappointed with his first class

B. he had prepared the topic before class

C. he wanted to calm down the students

D. he thought it was an easy topic

单项选择题