Such experiences are painful indeed， but is it not foolish to let them occupy our thoughts and precious time?
被动语态上一次介绍了被动语态的一般现在时和一般过去时形式，这里介绍其现在完成时和一般将来时形式:现在完成时形式: has/have + been + 过 去分词:The basket has already been emptied. 篮子已经 被腾空了。
