it has been a long time since+?since后面加什么形式?

it has long been assumed It has been a long time.Are you ok? it has been a long time. what is up It's a long time since还是It has been a long time since it been a long time.中的“been”,为什么用这个错了。it't been a long time. IT has been a long time since you dropped in---- 反义疑问句为何要说 hasn't it 而不说 didn't you it has long been known that It has been announced that it won't be long before our conutry------- an unmanned spaceship to explore the moon.A sends up B will send up It's been a long it's been a long 请问有首英文歌曲,歌词有句是honey,it has been a long time,……long long time 叫什么? It has a long neck . It has been a long time since we last wrote to each other. it has been a long time since+?since后面加什么形式? It’s has been quite a long time我想说好久不见 正确的应该怎么写 it has been the case for a long time that...这句话正确吗? It has been proven that information technology can give a firma long-lasting competitive advantage How long is it since he () his hometown?He () for nearly 10 years.A left;left Bhas left ;has leftChas left ;has been left Dleft ;has been left