男,3岁,在独自游戏时突然出现刺激性咳嗽,呼吸困难,其病因最可能是
A.大叶性肺炎B.自发性气胸C.左心衰竭D.气管异物E.右心衰竭
参考答案:D
The ________ in Chinese exports in recent years has resulted in a flood of inexpensive goods for
American consumers. [ ]
A. immigration
B. introduction
C. explosion
D. investment
管线的保温结构主要由()。