to be 与being 的区别

题目

to be 与being 的区别
His mum got lost in the big store,never (to be heard ofeing heard of) again.
为什么选前一个?

答案

此处非谓语动词作状语,二者皆可作状语但不定式一般作目的或结果状语[to do 前一般有only,表意想不到结果eg.I arrived at the station only to find the train gone]或在be +情感形容词后作原因状语eg.I am sorry to ...