TV has became part还是a part of our life.part是可数名词吧?为什么用part?

TV has became part还是a part of our life.part是可数名词吧?为什么用part? part是可数名词还是不可数名词? Here is part of his talk.为什么这里的part前面不加a?part不是可数名词么? Failure is part of life.为什么不是a part? taking a vacation became a part of American way life as a part of还是as part of作为...的一部分,书上是as part of为什么、 part a part of +什么名词 We were all part of it.用part 还是parts还是a part. part of our lives和 a part of our lives the internet has already become part of our life. a large part of 修饰可数名词还是不可数名词啊?