1.a while back 一段时间之前，不久以前

例句:We had a good rain a while back, but we need more now.
几个星期以前下了一场大雨，但我们现在更需要雨了。

2.abound in 充满，富于

例句:Examples abound in modern texts.
在现代的文章中这类例子不胜枚举。

3.absent from 缺席，不在

例句:He is absent from Hong Kong.
他不在香港。

4.absent-minded 心不在焉，健忘

例句:He's very learned but rather absent-minded.
他很有学问, 可是好忘事.

5.abuse of 对...的滥用；虐待

例句:Second, I will not tolerate abuse of our relationship with Member States.
其次，我不能容忍滥用我们与会员国的关系。

6.accede to 同意，答应；参加；就任，继任，即位

例句:They are ready to accede to our request for further information.
我们要是还需要资料,他们乐于随时提供。