硫醇汞盐紫外分光光度法测定青霉素钠含量
A．费休法B．铂电极C．汞-硫酸亚汞电极D．萘E．青霉素V
参考答案：B
To welcome the 29th Olympic Games, a lot of money ________ in improving the environment in Beijing. [ ]
A. take
B. spend
C. spent
D. is spent
发电机由空气置换为二氧化碳时，排气中二氧化碳的含量应大于（）%。
A、95
B、90
C、85
