Mr Green's already back,as Isaw him a moment ago.-__?I thought he wouldn't until tomorrow.填 IS he

不好意思,我下班的时候看到你的问题,不小心把那个对话框给关了,
我个人认为要选择is he
这是个主从复合句,从句只是起补充作用（有时是可以删除的）,主句才是主干.
所以第二句的回答语应该是针对主句的.
Mr Green's already back里面的's是is .你好，谢谢你抽空回答我地问题。这里's不是has 吗，already 不是和完成时态连用地吗?这句话用完成时可以这么说吗：Mr Green has already been back?对吗，谢了。Mr Green has already been back?可以这么说的。如果有 been ，那么就是has。你原题中没有，是个IS。