他一回来,我就会告诉他
因为是将来时 他一回来我就告诉他.（现在还没有回来）
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一.就...
as soon as possible 尽可能快
将来时：
I'll tell him as soon as I see him.我一见到他就告诉他.
过去时：
He left as soon as he heard the news.他一听到这事儿就走了.
现在时：
We need an ambulance as soon as possible!Someone has been hurt!
我们急需救护车,有人受伤了.
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as soon as连接的时间状语从句中,指未发生的动作,规律是：主句一般将来时,从句用一般现在时代替一般将来时
如：I will tell him the news as soon as he comes back.
指紧接着发生的两个短动作,主从句都用一般过去时
如 He took out his English books as soon as he sat down
就这两种情况 ,熟记就行.
在宾语从句中,当主句为与过去时的时候,从句必须用与主句相对应的时态,所以为了与主句动词said呼应,时间状语从句中的will look up应该对应为过去将来时态would look up,finds对应为found