1. The idea "happiness", to be sure, will not sit still for easy definition. 可以肯定的是，“幸福”这个概念很难定义。
2. He ought, to be sure, to have read over his lesson again, but that, you know, he could not do. 他当然应该再复习一遍功课，但你知道，他做不到。
3. To be sure, the battery still has a long way to go before the nightly recharge completely replaces the weekly trip to the gas station. 诚然，在夜间充电完全取代每周去加油站之前，电池还有很长的路要走。
4. To be sure, there is a process more immediately responsive to the people's will might have ousted Lincoln and Washington in their unpopular moments. 诚然，这一进程能更迅速地响应人民的意愿，就可能在林肯和华盛顿不得人心的时刻将他们赶下台。
5. England must win this game to be sure of qualifying. 英格兰队必须拿下这场比赛才能确保获得资格。
