若|a-1|+|b+2|=0，则a-b=（ ）。
3
评估慢性阻塞性肺疾病(COPD)严重程度的指标是以下哪一项
A．FEV1/FVCB．FEV1预计值C．RV/TLCD．DLCO/VAE．DLCO
Swift is a master （）, his satire is usually masked by an outward gravity and an apparent earnestness which renders his satire all the more powerful.
