attach to 使属于，使参加

attain to 达到(理想的状态)

attend on 照顾，侍候

attend to 专心；照顾，护理

back and forth (前后)来回地，往返

back away 逐渐后退

back down off 放弃，让步，退却

back of 在…的后面；在…背后

back out of 收回(诺言等)

back up 支持，援助；倒退

bank account n.银行账户

base on phr.以…（为）根据

based on 以…为基础

be able to phr.能，会

be about to 即将(做)

be absorbed in 专心致力于…

be abundant in …富于，…丰富

be accustomed to 习惯于

be acquainted with 开始认识；开始了解

be addicted to 沉溺于；使吸毒成瘾

be adequate for 适合

be afraid of phr.害怕

be alike to 与…相同，与…相似