—Excuse me. ______ is the bookshop?
—There it is. [ ]
A. How
B. What
C. Where
D. Who
答案:C
上消化道大出血最常见的原因是
A.胃癌
B.出血性胃炎
C.门脉高压症
D.胃十二指肠溃疡
在各轴承的进油口前,为什么要装节流孔板?