副詞 to be sure:

1. admittedly
   同義詞：without doubt, no doubt

1. Book early if you want to be sure of a seat.
   要想十拿九穩(wěn)有個座位，那就早訂座。
2. He is clever, to be sure, but not very hard-working.
   他聰明是聰明，但是不怎么勤奮。
3. I left a message so as to be sure of contacting her.
   我留下了張條子以便與她取得聯(lián)系。
4. To be sure, he is young, but he is very experienced.
   他確實很年輕，但他很有經(jīng)驗。
5. He likes to be sure of his bodily comforts.
   他注重身體上的舒適。
6. Joan's not pretty, to be sure, but she's very intelligent.
   當然，瓊并不漂亮，可她非常聰明。