is being 和are being

题目

is being 和are being
适合什么时候用?请举例
附加提问：过去式could后面不用pat tense
比如：i could dance very well when i was still young..

答案

is being 和 are being 都是被动语态的正在进行时态 .is 和 are的使用取决与主语的人称数：一般情况下,第三人称单数就用 is ；you 及复数就用 are 了：eg：You/they are being told how to dance by the teacher at ...