计量单位ng是
A．毫克 B．毫微克 C．微微克D．微克 E．毫微升
参考答案：B
代理报检单位办理代理报检注册登记时应有不少于15名经检验检疫机构考试合格并取得《报检员资格证》的人员。
22. Food aid______ is the key to______ the problem _______ now.
A．only, solve, discussed
B．alone, solving, being discussed
C．merely, solving, being discussed
D．alone, solve, being discussed
