问题
单项选择题 A1型题
对一种疫苗的效果进行双盲研究，是指（）
A.观察者和受试者都不知道哪些受试者接受疫苗，哪些受试者接受安慰剂
B.研究设计者和实施者都不知道哪些受试者接受疫苗，哪些受试者接受安慰剂
C.观察者和受试者都不知道安慰剂的特征
D.研究设计者和实施者都不知道安慰剂的特征
E.以上全不对
答案
参考答案：A
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对一种疫苗的效果进行双盲研究，是指（）
A.观察者和受试者都不知道哪些受试者接受疫苗，哪些受试者接受安慰剂
B.研究设计者和实施者都不知道哪些受试者接受疫苗，哪些受试者接受安慰剂
C.观察者和受试者都不知道安慰剂的特征
D.研究设计者和实施者都不知道安慰剂的特征
E.以上全不对
参考答案：A
| 完形填空。 |
| London is such a wonderful city. It is very large. The Thames River (泰晤士河) runs 1 the city from west to east. So the city has 2 parts, the South and the North. In the North are important buildings, shops, big parks and interesting places. The weather in London is good. In winter it is not very cold and in summer it is not very hot 3 the city is near the sea. People 4 that London is a foggy (多雾的) city and it often rains. It is true. Last year, when I 5 in London, I met one of the thickest fogs in years. You could not 6 your hand in front of your face. Cars and buses moved along with their lights on. When evening fell, the weather 7 even worse. 8 the buses and cars stopped. I had 9 important meeting on the other side of the town, but it was not easy to find a car. I had to arrive there 10 . |
| ( ) 1. A. about ( ) 2. A. two ( ) 3. A. because ( ) 4. A. speak ( ) 5. A. be ( ) 6. A. look ( ) 7. A. turn ( ) 8. A. Each ( ) 9. A. a ( ) 10. A. walk | B. through B. four B. or B. tell B. am B. look at B. become B. Every B. an B. on foot | C. in C. five C. so C. say C. was C. see C. grow C. None C. the C. by bus | D. along D. six D. but D. talk D. were D. saw D. got D. All D. \ D. by car |