有关常规细胞培养箱气体比例的描述，下列正确的是（）
A．1%CO2，99%空气的CO2培养箱
B．2%CO2，98%空气的CO2培养箱
C．3%CO2，97%空气的CO2培养箱
D．4%CO2，96%空气的CO2培养箱
E．5%CO2，95%空气的CO2培养箱
参考答案：E
解析：
常规细胞培养箱的气体比例应为5%CO2，95%空气的CO2。故正确答案是E。
Passage 1
What is this talk mainly about a. The role of youth in bringing out new form of popular culture. b. The role of television in mixing together different cultures and traditions. c. How British cultural life is influenced by people coming from different backgrounds. d. How the minority groups in Britain struggle to adpat themselves into the mainstream life.