besureabout的用法及例句

　　be sure of 與 be sure about 的區別：

　　be sure of 確信

　　例句：She looked over her shoulder to be sure of her footing.她扭頭看了看后面以確認自已是否站穩了.

　　be sure about 對.很有把握

　　例句：You can be sure about their interest in it.你可以肯定他們對引很感興趣.