问题 单项选择题 A1型题

对一种疾病的病因的某种可疑因素进行病因学研究时,可采用描述性方法或实验性方法,这两种方法的基本区别是,在实验性调查研究中()。

A.实验组和对照组的样本大小相等

B.这种研究是前瞻性的

C.实验组与对照组总是一致的

D.由研究者决定哪一个组暴露于可疑因素,哪一个组做为对照组

E.使用对照的方法

答案

参考答案:D

单项选择题
单项选择题

I will always remember my mother’s last few days in this world.
On February 14th, 2000, my class went on a field trip to the beach. I had so much fun. When we returned to school, my teacher told me to go to the headmaster’s office. When I got into the office, I saw a police officer. Suddenly I realized something was wrong. The police officer told me what had happened and we went to pick my sister up. After that, we went to the hospital and waited. Time went slowly. Finally, we got to see our mother. It was terrible.
On the next day, the headmaster came and told my two teachers what had happened. I was taking a rest that day. I knew it had something to do with my mother. I kept thinking that she either died or had gotten better. How I wished that she had gotten better. When my teacher took me outside, my sister ran up to me. She started crying, "She’s gone. Teresa, mommy’s gone. She’s dead. " I couldn’t believe it. We jumped into the car and drove straight to the hospital. Most of my family were there. The silence was terrible. I knew I had to say goodbye.
Today when I look back, I still miss my mother very much, but I know that I will live. My mother was a p mother, who had the biggest heart. My mother was an angel walking on the earth. I will always remember her as living. When someone is asked who their hero is, they usually say someone famous, like Michael Jordan or Britney Spears. When someone asks me who my hero is, I tell them, my mother. My mother lives every day. That is what makes her at rue hero.

The writer must think her mother is a ______ woman.

A.famous
B.free
C.rich
D.great