A.1/2 B.1/3 C.1/4 D.1/5
A.等于B.小于C.略小于D.大于
A.H=H1+H2 B.H≥H1+H2 C.任意單個(gè)揚(yáng)程<H<H1+H2 D.H<任意單個(gè)揚(yáng)程