1 . 被
Troops tried to enter the building which had beencaptured and wired with explosive charges ., 军队试图进入这座已经被占领并绑满炸药的建筑.
2 . 是
beemistress 养蜂女been是beep 哔哔声
3 . 过
Close contacts have beenplaced under medical observation and all remain well ., 对于和他有过密切接触的人现在置于医学观察之下 , 现在都很健康.
4 . 了
i cant recall how long it has been., 我回忆不起来多长时间了.
been英音:[bi:n]美音:[bɪn] been be的过去分词,是 has been 用于完成时,表示“已经” eg. Scientists think that there has been life on Earth for millions of years 科学家认为生命存在于地球已经有几百万年了。 have been done现在完成时的被动形式,表示已经被完成 have been doing现在完成进行时,表示到现在为止仍然在进行。 The work has been done.工作已经被完成了。强调结果 They have been playing foot