答案 0 :(得分:1)
我做了一个小实验,重要的部分是rank=same
:
digraph g {
rankdir=LR
node [shape=box ]
Petroleum
{rank=same Benzene;Xylene;Butanes}
{rank=same Ethylbenzene;Cyclobenzene;Cumene;"p-Xylene";Toluene}
Petroleum -> Benzene
Petroleum -> Xylene
Petroleum -> Butanes
Petroleum -> Toluene
Benzene -> Ethylbenzene
Benzene -> Cyclobenzene
Benzene -> Cumene
Xylene -> "p-Xylene"
}