人将自己和动物区别开来的决定因素是人有意识。( )
参考答案：错
在实际工作中，常用于分离石膏与塑料材料的分离剂是（）。
A.藻酸盐水溶液
B.皂甲溶液
C.甘油
D.凡士林
E.乙二醇
— Where is Zhang Ming?
— Oh, don't you know he _____ to Beijing to see his parents and he'll be back tomorrow.[ ]
A. has gone
B. has been
C. had gone
