I _____ stay at home yesterday. [ ]
A. have to
B. has to
C. had to
D. must to
答案:C
对完全垄断厂商来说,()。
A.提高价格一定能增加收益
B.降低价格一定会减少收益
C.提高价格未必能增加收益,降低价格未必减少收益
D.以上都不对
颅脑外伤经鼻气管插管前应排除()
A.牙齿松动
B.下颌关节脱位
C.下颌骨骨折
D.颅底骨折
E.舌外伤