However in some occasions such as inviting somebody else to participate my birthday party, I'll write an invitation letter, since it is more formal way to inform.

然而，在一些非常正式的场合，比如：邀请别人参加我的生日会，我也会写要邀请信。毕竟这是一种更为正式的方式。

youdao

However in some occasions such as inviting somebody else to participate my birthday party, I'll write an invitation letter, since it is more formal way to inform.

然而，在一些非常正式的场合，比如：邀请别人参加我的生日会，我也会写要邀请信。毕竟这是一种更为正式的方式。

youdao