be sure 怎么用
问题描述：
be sure 怎么用
答
一定要
答
1）意思：一定,必须2）用法：be sure+不定式,表示说话人对句子主语作出的判断,认为句子主语“必定”、“必然会”、“准会”如何如何.It is sure to rain．天一定会下雨.He is sure to have known about that．他准会...