It is/was time that 的用法

1。强调结构：It is/was 。。。 that 。
例句：It was at 10 o'clock that I heard the news。
2。表示时间例如：It was 10 o'clock when I heard the news。
3。表示“现在离（某事发生）已经有（一段时间）了。”