And also that we know that the zero does not count as a node, if per se I actually had managed to hit zero in drawing that, so the correct answer would be the bottom one there.

另外你们要知道零点不是节点，假设说我确实把零点画成０了，那正确的结果就是底下这个。

麻省理工公开课 - 化学原理课程节选