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，并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.
他們說到第二個月底為止，這項工程就已經不停地進行了3年了。
將來完成時(will have done)
�、俦硎疽粋�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.
�、诒硎疽粋�動作延續到將來某個時間，并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，并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。