這個是強調(diào)句型.
It is +sth/adj +that.
由該句型中it 是形式主語,真正的主語是that 引導的主語從句,常譯為”清楚（顯然,真的,肯定．．．）” 是主語從句最常見的一種結(jié)構.It is urgent that the acte problem of air pollution in the city be solved 是強調(diào)urgent
所以嗎,that 后的從句中要用虛擬語氣（should + 動詞原形）,should 可以省去.建議記住該句型中的形容詞.其它例句It is important that we (should) learn English well.
下面我們針對I met Li Ming at the railway station yesterday.句子進行強調(diào).強調(diào)主語：It was I that (who) met Li Ming at the railway station yesterday.強調(diào)賓語：It was Li Ming that I met at the railway station yesterday.強調(diào)地點狀語：It was at the railway station that I met Li Ming yesterday.強調(diào)時間狀語：It was yesterday that I met Li Ming at the railway station.
祝好!