be sure of/ be sure to do/ be sure that
Ⅰ.be sure of 确信对有把握后接名词、代词或动词-ing 形式，表对客观事物有肯定的认识和判断，主语必须是人。如：
① As David joined our team, we are sure of winning the game this time.
由于David参加了我们的球队，我们这次有把握取胜。
② You may be sure of his honesty. 你可以确信他的诚实。
Ⅱ.be sure to 一定，肯定，后接不定式，往往表示局外人的推测，评论，主语不一定是人，如：
① It is sure to rain tomorrow. 明天一定会下雨。
② He is sure to win.他一定会赢的。
▲ 用于祈使句时作务必，切切之意，如：
① Be sure to come tomorrow. 你明天一定要来
② Be sure to forget it . 千万别忘了。
Ⅲ. be sure that 从句。认为一定会主语必须是人，连词that 可省略。它后面还可以接由wheher, 或where, when, who 等引导名词性从句。这时主句通常是否定式。如：
① He is wure that he will succeed. 他确信会成功
② I am not sure where I left my notebook. 我不能确定我的笔记本丢在什么地方了。
blind in / blind to
