during [介词] 在...期间 Ex: The museum offers guided tours during certain hours of the day . 博物馆在一天中的某些时段期间提供导览。
available [形容词] 可用的 Ex: She made herself available to answer any questions the team had about the project . 她让自己有空回答团队关于项目的任何问题。
previous [形容词] 以前的 Ex: His previous attempts at solving the problem proved unsuccessful . 他之前解决问题的尝试证明是不成功的。