btw is usually followed by contents a bit related to the context.
p.s. could be followed by a totally different topic.
x*****u 发帖数: 4750
3
btw一般出现在信件得主要内容里， to add a casual or not directly relevant
comment .
ps. 顾名思义一般都落在信件最后 就是当你写完一封信得main text时候发现要加一些
额外得东西 to write n post - after main text.
