问题描述:
tho old man ,_____abroad for twenty years ,is on the way back to his motherland
A.to work B.working C.to have worked D.having worked
为什么选D?最好分析一下其他选项!
A.to work B.working C.to have worked D.having worked
为什么选D?最好分析一下其他选项!
问题解答:
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