《大旗英雄传》结局:do sth to do/doing sth这个后面的to do/doing sth都是后置定语吗?区别在哪?

it is my frist time to do sth / or doing sth/or do sth? mean to do sth/ mean doing sth 什么意思? begin to do sth./doing sth.的区别在于? be happy/surprised to do sth后面这个to do sth充当着什么语? agree to do sth agree to do sth有吗? 用pefer to do sth rather to do sth造句 be rich( )to do sth help sb. do sth还是help sb to do sth? help sb. do sth还是help sb to do sth? prefer to do sth rather than do sth 是什么意思