第1个回答 2011-02-19
1.have been done 曾经被 e.g. Taiwan has been taken charge of by the Japanese.
2.have been doing曾经干过一段时间... e.g. I have been walking along the lake.
3. 4. 是现在分词形式,一般用作状语,如 Having been bitten by a dog, now I am not a dog fan.
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