be able to (do) 能(做),会(做) be about to (do) 即将,正要 be absent from 缺勤,缺课 be abundant in 富于,富有 be accustomed to 习惯于 be acquainted with 与……相识,熟悉 be active in 积极于 be afraid of 恐怕,害怕,担忧 be alive to 发觉,感觉,对……敏感 b...