诊断支气管哮喘的主要依据是
A.血嗜酸性粒细胞增高
B.有阻塞性通气功能障碍
C.反复发作的呼吸困难伴有哮鸣音
D.血清特异性IgE升高
参考答案:C
There ______ a desk and some chairs in my room. The desk is very nice. [ ]
A. are
B. is
C. has
D. have
压力容器的定期检验分为外部检查、内外部检验、耐压试验三种。