at first 首先，开始的时候
at large 未被捕获的，大多数
at last 终于，最终
at least 至少
at length 最终，详细地
at most 最多
at no time 从不，决不
at one time 曾经，从前曾
at the cost of 以……为代价
at the least 至少
at times 有时，间或
at…speed 以……的速度
attend on 照顾，侍候
attribute … to 把……归于
back up 后退，支持
base on 基于
be able to 能够，胜任
be about to 正打算
be accustomed to 习惯于
be associated with 与……有关，与……有关系
be aware of 意识到
be capable of 有能力干
be caught 遇到，陷入
be committed to 被交给┄，答应承担┄义务
be confined to 限制在，局限于
be confined/be restricted 受……限制
be dedicated to 奉献，献给
be devoted to 被用于，贡献给
be directed to 指向，针对
be drawn to 被┄所吸引
be due to 由于，因此
