载气在使用前必须经过净化，通常除去载气杂质在干燥管填充（）。
参考答案：硅胶分子筛活性炭
He proved himself a true gentleman and the beauty of his ________ was seen at its best when he worked with others.[ ]
A．advantage
B．appearance
C．qualification
D．character
为了满足管理的需求，会计科目的设置越细越好。
