下列哪几项不是食管异物的并发症（）
A.食管穿孔
B.反流性食管炎
C.皮下气肿
D.主动脉弓破裂
E.气管食管瘘
参考答案：B
--- Do you love teaching, Miss He?
--- I fell in love with teaching in 2000. I ________ for twelve years by this summer.
A．will teach
B．would have taught
C．has been teaching
D．will have been teaching
轻质材料按表观密度分为（）
A.准轻质材料
B.轻质材料
C.超轻质材料
D.混合轻质材料
E.一般轻质材料
