树脂的湿真密度是指(),即湿真密度=(),单位是()。
参考答案:树脂在溶胀后的质量与其所占的真实体积(不包括树脂颗粒之间的孔隙体积)之比;湿树脂的质量∕湿树脂真实体积;g∕mL
微量元素是指其含量低于人体总重量的()
A.1%
B.0.1%
C.0.01%
D.0.001%
E.0.0001%
His father has been ____ for months, which puts the family in a even worse situation. [ ]
A. out of his work
B. out of his job
C. out of work
D. out of a work