When the plane is to take off has not been announced 飞机何时起飞还没有宣布飞机何时起飞还没有:When the plane is to take off has not 为什么这边需要用过去分词加announced 这是什么形式.?
网友回答
announce 是人为动作 所以主语为 When the plane is to take off 起飞时间 的时候 主语是被announce 所以是 be announced
时间是被人宣布的
======以下答案可供参考======
供参考答案1:
has not been announced 现在完成时，have been done sth.，这边是被动语态
供参考答案2:
has not been announced -------是“被动语态”形式，解释为：还没有被通知。
供参考答案3:
这不是表示被动语态嘛！！！
供参考答案4:
首先分析句子成分，题中的句子是一个主语从句，主语是一个When the plan is to take off，我们把它替换成It，原句就变成It has not been announced，显然是一个现在完成时的否定句，现在完成时的语法楼主应当知道，所以在此就不用多说，for example, what you have asked hasn't bees solved now. 意思是您提的问题到现在还没解决。