爲了突出句子的`某個部分，我們可以使用強調句式。
常見的強調句結構是it 引導的句子。
It is 被強調部分+ that + 句子其他部分。
此結構強調的成分僅限於主語，賓語和狀語。
It is from the sun that we get light and heat.
It was not until I had read your letter that I understood the true state of affairs.
使用此句型時, 應注意以下幾點。
一般情況用It isthat如:
He read three books in the library yesterday.
It was he whoread three books in the library yesterday.
It was three books that he read in the library yesterday.
It was in the library that he read three books yesterday.
當被強調部分指人時, 可用that, 也可用who; 指物時, 只用that, 如:
It was Tom whoI met last week.
It is a new boke that his brother wants to buy.
強調狀語時, 只用that, 不用when、where. 如:
It is at 5 oclock that the train will arrive.
被強調的部分是主語時, 注意句子的謂語動詞和被強調的主語保持一致。