語法講解：強調句
一、強調句句型
1. 陳述句的強調句型：it is/ was + 被強調部分（通常是主語、賓語或狀語）+ that/ who（當強調主語且主語指人）+ 其他部分。
e.g. it was yesterday that he met li ping.
2. 一般疑問句的強調句型：同上，只是把is/ was提到it前面。
e.g. was it yesterday that he met li ping？
3. 特殊疑問句的強調句型：被強調部分（通常是疑問代詞或疑問副詞）+ is/ was + it + that/ who + 其他部分？
e.g. when and where was it that you were born？
4. 強調句例句：針對i met li ming at the railway station yesterday.句子進行強調。
強調主語：it was i that （who） met li ming at the railway station yesterday.
強調賓語：it was li ming that i met at the railway station yesterday.
強調地點狀語：it was at the railway station that i met li ming yesterday.
強調時間狀語：it was yesterday that i met li ming at the railway station.
5. 注意：構成強調句的it本身沒有詞義；強調句中的連接詞一般只用that， who，即使在強調時間狀語和地點狀語時也如此，that， who不可省略；強調句中的時態(tài)只用兩種，一般現(xiàn)在時和一般過去時。原句謂語動詞是一般過去時、過去完成時和過去進行時，用it was …… ，其余的時態(tài)用it is …… .
二、not … until … 句型的強調句
1. 句型為：it is/ was not until + 被強調部分 + that + 其他部分
e.g. 普通句：he didn't go to bed until/ till his wife came back.
強調句：it was not until his wife came back that he went to bed.
2. 注意：此句型只用until，不用till.但如果不是強調句型，till， until可通用；因為句型中it is/ was not …… 已經是否定句了，that后面的從句要用肯定句，切勿再用否定句了。
三、謂語動詞的強調
1. it is/ was …… that …… 結構不能強調謂語，如果需要強調謂語時，用助動詞do/ does或did.
e.g. do sit down. 務必請坐。
he did write to you last week. 上周他確實給你寫了信。
do be careful when you cross the street. 過馬路時，務必（千萬）要小心啊！
2. 注意：此種強調只用do/ does和did，沒有別的形式；過去時用did，后面的謂語動詞用原形。