將來(lái)完成時(shí)：

1.構(gòu)成：shall / will have + 過去分詞

2.功能：表示將來(lái)某時(shí)之前已經(jīng)完成的動(dòng)作。

→They will have been here for 5 years next Friday.

→By the end of next term, the students will have finished the book.

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過去將來(lái)完成時(shí)：

1.構(gòu)成：would / should have + 過去分詞

2.功能：表示從過去某個(gè)時(shí)間看將來(lái)某時(shí)之前已經(jīng)完成的動(dòng)作。

→He said that they would have arrived by seven o'clock.

?

將來(lái)完成進(jìn)行時(shí)：

1.構(gòu)成：shall / will have been + 現(xiàn)在分詞

2.功能：表示某一動(dòng)作將繼續(xù)到將來(lái)某時(shí)，且該動(dòng)作此時(shí)尚未發(fā)生。

→We shall have been staying here for four weeks when Tom arrives.

→It will have been raining for a week if it does not stop tomorrow.

注：此句型過于復(fù)雜，人們很少運(yùn)用，了解而已。