be sure of doing sth. 的意思是:确定做某事、以便于做某事。 例句:I left a message so as to be sure of contacting her. 我留下了张条子以便与她取得联系。
相似结构:be sure of sth. 保证某事、确保某事。 例句:①He likes to be sure of his bodily comforts. 他注重身体上的舒适。 ②Book early if you want to be sure of a seat. 要想十拿九稳有个座位,那就早订座。