在薄层定性鉴别中，最常用的吸附剂是（）
A.硅胶G
B.微晶纤维素
C.硅藻土
D.氧化铝
E.聚酰胺
参考答案：A
He is always the last one ______ school. [ ]
A. gets
B. to get
C. get to
D. to get to
These shoes are yours. Please _____. [ ]
A. put on them
B. put on it
C. put them on
D. put it on
