英语中的it强调句型主要用于强调句子的主语、宾语、时间状语或地点状语。其基本结构是：It+be+被强调部分+that（强调部分指人做主语时用who，指人做宾语时用whom）+句子的其他部分。例如：Mary met an old beggar in the street yesterday。It was Mary who/that met an old beggar in the street yesterday。（强调主语）It was an old beggar whom/that Mary met in the street yesterday。（强调宾语）It was yesterday that Mary met an old beggar in the street。（强调时间状语）It was in the street that Mary met an old beggar yesterday。（强调地点状语）需要注意的是，it强调句型不能用来强调句子的谓语部分。
not...until结构在强调句型中的应用也非常广泛。其构成形式是：It+be+not+until部分+that+句子的其他部分。例如：He didn't go to bed until his father came back。变为强调句型为：It was not until his father came back that he went to bed。原句中的didn't go部分中的not提前后，剩下did go变为went。本文开头提到的两个句子都是not...until结构用于强调句型。那么把这两句话变回正常的语序则为：1) He but he didn't make his most important discovery until after the war。2) The importance of Fleming's discovery was not fully recognized until World War II。
特殊疑问句也可以通过it强调句型进行强调。其构成形式是：特殊疑问词+be+it+that+句子的其他部分（用陈述语序）。例如：When did you receive the gift？对特殊疑问词when做强调：When was it that you received the gift？注意此句中的received是由did加receive结合而成的。
