创伤病人出现呼吸道梗阻原因有()
A.舌后坠
B.呼吸道粘膜水肿、血肿
C.异物、分泌物、凝血块阻塞
D.颌面部软组织损伤
E.颌骨骨折错位
参考答案:A, B, C, D, E
Do you want to write an e-mail _________ your friends?[ ]
A. to
B. in
C. at
供焦炉的循环氨水有何要求?