胆系疾病的首选方法是（）。
A.B超
B.口服胆囊造影
C.静脉胆道造影
D.平片
E.胃肠钡餐造影
参考答案：A
I think Mike is ____ student in my class. [ ]
A. more careful
B. the most careful
C. careful
D. careless
简述我国汽车消费特点。
