English Grammar

Verb "involve"
One of the meaning of the verb "involve" (often used in passive voice; usually followed by in or with) is to concern or associate significantly: eg
(1)many people were involved in the crime
and
(2)"all those who have been involved (concerned or associated significantly) in searching for the missing plane"

我想問為何這句子
I want to praise all those who have been involved in searching for the missing plane.用 have been involved這時態? 這又是什麼時態呢?
"Have been involved" is in passive voice. It, in present perfect tense, is used here because it refers to the action by all the people who were involved since the searching began up to the present moment when they are praised.

have been involved 的時態是 present perfect tense (現在完成式)，再配合 passive voice (被動式)。

上文解作「曾經被捲入參與搜救事件的人」

2014-05-11 17:41:08 補充：
說人的時候，involve 多用於 被動式～

He is involved in this event.

當然在主動式當中也可以使用：

The party involves his performance.

"have been involved"指的是已經參與的, 這是現在完成式(Present perfect tense), 表示在這一刻動作已經完成