請看例句：

He has finished writing his novel. 他已寫完了他的小說。

He had finished writing his novel by the end of last year. 去年年底他就寫完他的小說。

He will have finished writing his novel by the end of next year. 到明年年底他就會寫完他的小說了。

與一般現在時代替一般將來時一樣，在表示時間或者條件的狀語從句，通常要用現在完成時來表示將來完成時，而不能直接使用將來完成時：

I will go with you when I have finished my work. 等我完成工作之后我就同你去。

若不強調動作的完成(且不至于引起歧義)，有時也可用一般現在時：

I will go with you when I finish my work. 我完成工作后就同你去。

四、將來完成通常搭配的狀語

1. 用作狀語的介詞短語

There will have been a definite result before Friday. 星期五以前將肯定會有結果。

By next Christmas we’ll have been here for eight years. 到下一個圣誕節，我們在這兒就住了整8年了。

By now you will have guessed that I’m back in Ireland. 你現在應該已經猜出我回到了愛爾蘭了。

By the end of next week, I will have been a teacher for 25 years. 到下周末，我當老師就有25年了。

We’d better wait till 14 December. David will have had his exam by then, so he’ll be able to enjoy himself. 我們最好還是等到12月14日。到那時大衛就考完試了，這樣他就能夠玩得痛快。

2. 用作狀語的從句

If I don’t run, the train will have left.(www.hz123456.com) 如果我不跑，火車就會開走了。

If he turns it down, he will have lost the moral high ground to the president. 如果他拒絕的話，就會把精神上的優勢輸給總裁。

If you finish this job as well, you will have done far more than I expected. 假如你將這項工作干完的話，那你會干得比我預料的要多了。

If there was any scandal in that company, you can be sure that Bobby will have clocked it.  那家公司有任何丑聞，博比肯定會知道。