while“it”用法总结.pptVIP

知识要点 while的用法 (1)引导时间状语从句，意为“当…的时候, 在…期间”从句中的谓语动词应用延续性动词或表示状态的词； (2)引导让步状语从句,多用于句首。意为“尽管,虽然”； (3)While作并列连词用,意思为“而,然而”,表前后意义上的对比； (4)引导条件状语,意思是“只要”； (5)while可用作名词,意为“一会儿;一段时间”。 知识要点 while的用法 1. Some people waste food while others havent enough. 有些人很费粮食，然而有些人却吃不饱。 (然而) 2. We must strike while the iron is hot. 趁热打铁。(当…的时候) 3. While there is a way there is away. 有志者事竟成。 (只要) 4. While these experiments are interesting and useful, it is important to remember that they may not always tell us much. 虽然这些实验很有趣也有用，但是很重要的是要记住，这些实验也可能不会告诉你很多。 (虽然，尽管) 知识要点 while的用法 5. While there is life there is hope. 只要生命存在，就有希望。 (只要) 6. While she was listening to the radio, she fell asleep. 她听着收音机睡着了。 (当…的时候) 7. The son was having a good meal at home, while the parents were working in the fields. 儿子在家吃好饭而父母却在田里辛勤劳作。 (然而) 8. While he loves his students, he is very strict with them.. 虽然他爱他的学生，可是他对他们很严格。 (虽然，尽管) 知识要点 while的用法 1. I ought to have helped her, but I never could. 2. Honey is sweet, but the bee stings. 3. In some places women are expected to earn money while men work at home and raise their children. 4. Some people are wasting water while some people are fighting for water. while表示前后句形成“对比”关系，but只表达转折。 知识要点 It的用法 （一）作人称代词 1、it代替前面（或后面）的单数名词, 不可数名词或分句等所表示的事物。 You cannot eat your cake but have it. （it代替前面的cake） Although we cannot see it, there is air all around us. （it代替后面的air） They say he has left town, but I don’t believe it. （it代替前面They…town分句中的情况） 知识要点 2、代替有生命但不能或不必分阴阳性的东西（包括婴儿）。 Yesterday we saw a big tree. It was fully twenty metres high. （it代替前面的tree） The baby cried because it was hungry. （it代替前面的baby） 知识要点 3、在某些习惯说法中，可以代替人。 1)---- Someone is knocking at the door, Peter. ---- Who is it? ---- It’s me. 2)---- Who are singing? ---- It is the children. 3)---- The light is still on in the lab. It must be the third-year students doing the experiment. 知识要点 4、it与one的区别：这两个词都可以代表前面说过的单数名词，但it用于同名同物；one则用于同名异物。It还可以指不可数名词。 1)---- Do you still