乙型肝炎疫苗第一次接种年龄为（）
A.初生时
B.1个月
C.3个月
D.8个月
E.1岁
参考答案：A
Professor Smith, along with his assistants, on the project day and night to meet the deadline
(截止日期). [ ]
A. work
B. working
C. is working
D. were keeping
薄层色谱法测定黄曲霉毒素B1含量时，在波长为多少的紫外光下照射产生荧光？
