had been done是什麼時態

過去將來完成進行時：(would have been doing)

表示動作從過去某一時間開始一直延續到過去將來某一時間，期間一直有規律在進行、不曾間斷，並且有可能繼續延續下去。

例：They said that by the end of the following month, the project would have been being worked for 3 years.

他們説到第二個月底為止，這項工程就已經不停地進行了3年了。

將來完成時(will have done)

①表示一個動作到將來某個時間為止已經完成，強調對將來那個時間產生的影響。

例：Pick me up at 8 o'clock,I will have had breakfast by then.

早上8點鐘你來接我,到時我已經吃完早飯了.

②表示一個動作延續到將來某個時間，並且有可能繼續延續下去。

例：The conference will have lasted a full week by the time it ends.

會議從開始到結束將持續整整一個星期。

將來完成進行時：(will have been doing)

表示一個動作延續到將來某個時間，期間一直有規律在進行、不曾間斷，並且有可能繼續延續下去。

例：By the end of next month, the project will have been being worked for 3 years.

到下個月底為止，這項工程就已經不停地進行了3年了。