受益了，学习了。有一点敢问前辈一下：

为什么不把这个从句当作主语从句来分析，把IT 当作来代替这个主语从句的：that a single man in possession of a good fortune must be in want of a wife.？

可不可以理解成：That a single man in possession of a good fortune must be in want of a wife is a truth universally acknowledged。？

而如果能把这个从句当作主语从句来分析，主从句之间的逗号作用就显得大了。