【单选题】A 3-year-old boy has had a cough, headache, and slight fever for 5 days. He is now having increasing respiratory difficulty. On physical examination, his temperature is 37.8° C, pulse is 81/min, respi...
【单选题】A 3 -year-old boy has had a cough, headache, and slight fever for 5 days. He is now having increasing respiratory difficulty. On physical examination, his temperature is 37.8°C, pulse is 81/min, respi...