反跳痛的发生机理是
A.腹腔内有关炎症病灶
B.腹膜的壁层受炎症累及
C.腹腔内有出血
D.腹膜的脏层受炎症累及
E.胃或肠穿孔
参考答案:B
A little boy wrote____ "U" and___ "n" on the wall.
A.a; an
B.an; a
C.an; an
D.a; a
持用通勤、就医乘车证,除换乘外,中途下车无效。()