______ of danger in the street at night, she had to go home with a friend ____ her.

A．Warning; following

B．Having warned; following

C．Warned; followed

D．Having been warned; following

女性，55岁，有咳嗽、咳痰史8年，伴喘息，入院前3天因受寒咳嗽、喘息加重，咳黄痰入院。入院时查体：桶状胸，叩诊过清音，肺肝浊音界在右锁骨中线第7肋间，双肺干、湿性哕音及散在哮鸣音。肺功能：FEV₁/FVC为56%，MVV 60%，VC降低，RV/TLC为43%。住院第2天，因下床时用力过度出现胸痛，呼吸困难，查体：右胸叩诊鼓音，呼吸音消失，发绀。

该患者诊断阻塞性肺气肿最重要的指标是

A．VEV₁/FVC% ↓

B．RV/TLC＞40%

C．MVV ↓

D．VC ↓

E．RV ↑