下列不能体现细胞之间的统一性的是[ ] A．从元素水平看，组成各种细胞的化学元素

数据库管理系统常见的数据模型有层次模型、网状模型和 【5】 3种。

平行四边形是轴对称图形。[ ]

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 finally 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. "Okay, 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 forest 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 stories

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

输卵管妊娠破裂多见于

A．伞部妊娠

B．壶腹部妊娠

C．峡部妊娠

D．间质部妊娠

某企业在三年前就准备购建一条生产线，并已经做了前期调查和可行性分析，支付相关费用8万元。但由于资金没有落实，该项目被搁置下来。现在已经筹集到该项目所需要的资金，企业重提旧事。

该生产线购置费2500万元，预计可使用10年，预计每年将发生维护修理费用 15万元，预计报废时可得净残值收入20万元，同时该生产线需要追加配套的流动资金300万元。生产线投产后，估计每年扣除付现成本后的营业收入为500万元。企业的资本成本为6%。

请分析案例，并回答下列问题：

除以上内容外，在计算投资项目的现金流量时还应考虑（）。

A．本项目的机会成本

B．项目投产后对本企业其他部门或产品的影响

C．本项目的沉没成本

D．企业管理者素质