药品按药理作用分类,下列药物哪些属于镇痛药()
A.吗啡
B.杜冷丁
C.阿司匹林
D.对乙酰胺基酚
参考答案:A, B
Iraq has _____ too many wars since 1990s, making his people _____ a lot.[ ]
A. got through; pay
B. looked through; face
C. gone through; suffer
D. passed through; destroy
当磨机喂料不足时,磨机压差上升。