Has it been been announced if the planes are to take off?这个句子对吗?

it has been since.用法 It has been in my it is/has been= It's has been accepted it has long been assumed it's always been you(It has always been it has been可以缩写成it's been it's been.的全称是不是 it has been... has been It has been raining these days. It has been e()hot this week. it has long been known that it has since been rebuilt怎么翻译 造句it has been +时间段+since从句it has been +时间段+since从句 it has been used和it has been in use有什么区别吗 是It has been paid还是 It has been paid for? 为什么是It has been paid而不是 It has been paid for? it has been done 谓语it has been done 这句话done作表语还是been done做谓语?