A.0.56V B.0.54V C.0.46V D.0.35V
A.快速進(jìn)行 B.開(kāi)始幾滴要慢,以后逐漸加快,最后緩慢 C.始終緩慢 D.開(kāi)始快,然后慢,最后逐漸加快
A.H2SO4 B.HCl C.HNO3 D.HAc