以下哪些是常见的光学元件( )。
A. 光电池
B. 光电管
C. 光电倍增管
D. 光敏电阻
When is the best tourist season in Aegean Sea ?
A. From November to February
B. From January to June
C. From April to October
D. From May to September
Athens hosted modern Olympic Games twice.
A. 对
B. 错
在Excel 2010中执行降序排列,在序列中空白单元格被()。
A. 放置在排序数据的后面
B. 放置在排序数据的前面
C. 不被排序
D. 保持原始次序