语境自主领悟先观察原句后自主感悟１．There is no doubt that the earth isbecoming warmer and that it is human activitythat has caused this global warming ratherthan a random but natural phenomenon．２．It was a scientist called Charles Keeling whomade accurate measurements of the amountof carbon dioxide in the atmosphere from １9５7 to １997．３．They also agree that it is the burning ofmore and more fossil fuels that has resulted inthis increase in carbon dioxide．１．例１中的it is．．．that．．．为强调句型，在这个句型中，it没有意义，只是引出被强调的成分。
此处强调的是同位语从句的主语human activity。
２．例２中的it was．．．who．．．为强调句型，此处强调的是主句的主语a scientist。
被强调的成分是表示人的词，故也可用who。
３．例３中的it is．．．that．．．为强调句型，此处强调的是宾语从句的主语the burning of more andmore fossil fuels。
一、强调句型的基本结构强调句型的基本结构为：it is/was＋被强调部分＋that/who＋其他成分１．此结构中it 没有意义，只是引出被强调部分。
２．此强调句型只能强调主语、宾语、状语，不能强调谓语。
３．被强调的成分是表示人的词时用who/that，而被强调成分是其他时（事物、时间、地点等）只能用that。
It was John who/that bought an old bike yesterday in a marketplace．是约翰昨天在市场上买了辆旧自行车。
（强调主语）It was an old bike that John bought yesterday in a marketplace．昨天约翰在市场上买的是辆旧自行车。
（强调宾语）It was yesterday that John bought an old bike in a marketplace．约翰是昨天在市场上买了辆旧自行车。
（强调时间状语）It was in a marketplace that John bought an old bike yesterday．昨天约翰是在市场上买了辆旧自行车。
（强调地点状语）It was because the water had risen that they could not cross the river．正是因为水涨了，他们没能过河。
（强调原因状语）[即时演练１]用强调结构对下面句子中的划线部分进行强调Nancy saw your sister in Tokyo last week．１It was Nancy that/who saw your sister in T okyo last week．（强调主语）２It was your sister that/who Nancy saw in T okyo last week．（强调宾语）３It was in Tokyo that Nancy saw your sister last week．（强调地点状语）４It was last week that Nancy saw your sister in Tokyo．（强调时间状语）二、强调句型的一般疑问句式和特殊疑问句式１．一般疑问句式：Is/Was it＋被强调部分＋that/who＋其他成分？Was it during the Second World War that he died？他是二战期间死亡的吗？２．特殊疑问句式：特殊疑问词＋is/was＋it＋that＋其他成分？Why is it that you put off the meeting？你为什么推迟会议呢？Where was it that you lost your car？你是在哪儿丢的车？[即时演练２]用强调结构对下面句子中的划线部分进行强调１How did you forget to lock the door？How was it that you forgot to lock the door？２Did he work where his father had studied？Was it he who/that worked where his father had studied？三、对not．．．until．．．结构的强调not．．．until．．．结构的强调句型为“It is/was not until．．．that．．．”，在这一固定句型中，由于not已经前移，that后只能用肯定形式。
He didn't go to bed until ten o'clock．→It was not until ten o'clock that he went to beＤ．直到１0点他才睡觉。
I didn't realize it until I got off the bus．→It was not until I got off the bus that I realized it．直到下车之后我才意识到这事。
[即时演练３] 强调下面句子中的not．．．until．．．结构１I didn't hear from her until last summer．It was not until last summer that I heard from her．２He did not realize his mistakes until the plan was completely ruineＤ．It was not until the plan was completely ruined that he realized his mistakes．四、使用强调句型的几个注意事项１．若被强调成分是主语，who/that之后的谓语动词应该在人称和数上与被强调的主语保持一致。
It is he who/that often helps me with my English．是他经常帮我学英语。
It is trees that are planted on the hillside every year．每年都在山坡上种的是树。
２．若被强调成分是作主语的代词，用主格；若是作宾语的代词，则用宾格。
It was he that helped me yesterday．昨天帮我的人是他。
It was me that he helped yesterday．他昨天帮的人是我。
３．强调句中只用两种时态，即一般现在时和一般过去时。
原句谓语动词是一般过去时、过去完成时和过去进行时，用It was．．．that/who．．．，其余的时态用It is．．．that/who．．．。
It is you who/that are to blame．是你该受到指责。
It was in the classroom that I left my umbrellＡ．我把雨伞落在了教室里。
[名师点津]强调句型最容易与定语从句、主语从句和状语从句等混淆，区分它们的关键在于：如果把句子中的It is/was和that/who去掉，剩下的部分还是一个完整的句子，并且句子意思依然完整，则此句为强调句型；否则，应仔细分析句子，判断该句是何种从句。
It was at the school gate that I met an old friend of mine．我是在学校大门口遇见一位老朋友的。
（强调句型）It was such a hot day that even the crops withereＤ．天气如此炎热，连庄稼都枯萎了。
（结果状语从句）[即时演练４] 用所给词的适当形式填空１It was Susan and John who were（be）absent from school yesterday．２It is this experience that helps（help）me better understand the proverb “Practice makes perfect”．单句语法填空１．It was at midnight that she was woken up by a phone call．２．It was（be）because of the most beautiful village teacher—Xiao Shan's strong determination that he formed the woman football team in the poor areＡ．３．It is either he or you who/that are in charge of the project and supposed to finish it punctually．４．He was so busy yesterday that it was not until late at night that he finished his work．５．You are waiting at a wrong place．It is（be）at the hotel that the coach picks up tourists．6．It was when we were returning home that I realized what a good feeling it was to have helped someone in trouble．7．Bach died in １7５0，but it was not until the early １9th century that his musical gift was fully recognizeＤ．8．It's not doing the things we like，but liking the things we have to do that makes（make）life happy．9．It was the middle of the night when my father woke me up and told me to watch the football game．１0．It was with the help of the local guide that the mountain climber was rescueＤ．。