He was seated是被动语态吗?为什么用was?用is不行吗?

The cup is broken,是被动语态,为什么要用IS而不用was 1.He was fired.是被动语态吗? after they were seated为什么用被动语态 he has been there since 1997s是完成时被动语态吗?如果是为什么要用被动语态?不可以说成he 下面句子为什么用的是被动语态was finished而不是过去完成时had been finished 被动语态的 be,什么时候用 is,什么时候用was?The CD is made in Japan.为什么be用is, the girl was able to explain what had happened.不是被动语态为什么用was Is this book is written by Bill Gates 到底是用is还是was 我知道是被动语态 is it broken 这个为什么不是 was it broken?我知道这个是被动语态 向老师请教：to be taught在下句中是否是不定式的被动语态做表语?为什么不直接用was taught呢? he was seated,with his eyes fixed on the gound.为什么不能用fixing he was a boy,she was a girl 为什么是用was而 不用is