It's unfortunate that we still do not know what really happened to Malaysia Airlines flight MH370. Amid the drama and accusations surrounding the mystery, I want to praise all those who have been involved in searching for the missing plane. They are true heroes and heroines.
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?