上消化道出血最常见的病因是（）
A.急性胃黏膜损害
B.胃癌
C.食管胃底静脉曲张破裂
D.消化性溃疡
E.食管贲门黏膜撕裂综合征
参考答案：D
—I used to get up at six o'clock to catch the early bus.
—________. But now I usually get up after seven o'clock. [ ]
A. So I did
B. So was I
C. So I was
D. So did I
铝电解常用添加剂主要有：氟化铝、（）、氟化镁、氟化锂。
