总样
参考答案：
从一采样单元取出的全部子样合并的煤样。
My English teacher has given me so much help that I really want to do something for him _____. [ ]
A. in return
B. in fact
C. in surprise
D. in turn
进入疟区时，用于病因性预防的首选药是（）
A.伯氨喹
B.氯喹
C.乙氨嘧啶
D.磺胺多辛
E.奎宁
