为了明确上消化道出血的病因和部位,可选用哪项检查()
A.双气囊三腔管
B.X线钡餐检查
C.胃镜
D.选择性腹腔动脉造影
E.以上都可以
参考答案:C
Demand for these books is high recently, _______their high price. [ ]
A. although
B. despite
C. even if
D. while
出口援外物资无须办理报检手续。