问题
单项选择题 A1/A2型题
某人进行了下列疫苗试验,随机选择1000人,注射疫苗后,随访10年,接种者中80%未患该病,此疫苗效果()
A.很好
B.得不出结论,因为无注射疫苗的对照
C.不是很有效,因为尚有20%患病
D.无肯定结论,因为未做统计学检验
E.该病疾病的发生率是20%
答案
参考答案:B
某人进行了下列疫苗试验,随机选择1000人,注射疫苗后,随访10年,接种者中80%未患该病,此疫苗效果()
A.很好
B.得不出结论,因为无注射疫苗的对照
C.不是很有效,因为尚有20%患病
D.无肯定结论,因为未做统计学检验
E.该病疾病的发生率是20%
参考答案:B
小题2: . His schoolbag is on his desk, too. A model plane is on the floor. 小题3: . The teacher is Miss Smith. She is a Chinese teacher. 小题4: . The girls are Linda and Jane. They are 11. The boy is Mike. He is 12 years old. 小题5: . We are in Class 3, Grade 7. This is a nice picture. I like it very much. |