四六级

　　进入暑假状态的同学们都有什么安排与计划呢？有没有为学习英语留出一些时间？尤其是语法知识相对薄弱的同学，暑假正是恶补的最好时期。从今天开始小编每天为大家整理一些英语四级语法基础知识，希望大家认真复习。

        2017年12月英语四级基础语法知识大全

　　复杂结构的强调句式

　　句子结构比较复杂时，尤其是当被强调成分比较复杂时，有的同学们就不能识别句子所用的强调结构，从而不能正确作出选择。如：

　　It was lack of money, not of effort, that defeated their plan. 他们的计划受挫，原因是缺少钱而不是没有尽力。

　　It was more in sorrow than in anger that he criticized his former colleague. 他批评以前的同事，并非出于气愤而是为他惋惜。

　　It is the protection for the trees that really matters, rather than how many trees are planted. 真正重要的在于对树木的保护，而不在于种了多少树。

　　As far as he's concerned, it's not doing something wrong that matters, but not being caught doing something wrong, 就他而论，重要的不是做错事，而是做错事不被抓住。

　　请看两道题：

　　(1) It is not who is right but what is right _______ is of importance.

　　A. which B. it C. that D. this

　　答案为C。此题考查it is…that…这一强调句式，被强调的是not who is right but what is right，全句意为：重要的不是谁是对的，而是什么才是对的。

　　有时考查not…but…的同义结构…rather than…与强调结构的综合运用。如：

　　(2) It is what you do rather than what you say _______matters

　　A. that B. what C. which D. this

　　答案为A。被强调成分为what you do rather than what you say，全句意为：重要的是看你怎么做，而不是看你怎么说。

　　强调句与从句的比较

　　1. 强调句与主语从句的比较

　　强调句将句子中的it is / was …that同时省去，句子仍然成立;而主语从句将that与后面部分代替it，成立。如：

　　(1) It is Li Lei's brother that you met in the street yesterday. 你昨天在街上所见到的就是李蕾的兄弟。

　　本句若将It is 及 that同时省去为：You met Li Lei's brother in the street yesterday. 句子同样成立，因此前面的句子是强调句型。

　　(2) It is exciting that we have succeeded in sending up Shenzhou V. 我们成功地发射了神舟五号这件事情真令人兴奋。

　　本句若将It is 及 that同时省去为：We have succeeded exciting in sending up Shenzhou V. 显然句子错误，因此，前面句子不是强调句型，而是主语从句。

　　2. 强调句与定语从句的比较

　　◎强调句中的It没有实际意义，It be与that可同时被省略;而定语从句中的It是主语，It be与that不可同时省略;

　　◎强调句型中be的时态须跟后面句子的时态相一致;而定语从句中主句谓语动词be的时态须由主句的时间确定;

　　◎强调句将句子中的that不能省略，并且即使前面的名词是事物时，也不能将that换成which;而定语从句中的that作宾语时可被省略，并且当先行词是事物时可用which代替。

　　◎当it be后面的时间、地点名词作主语、宾语或表语时，引导词可用that / which;而作其他成分时，引导词须用when / which。如：

　　(1) It is an English book (that / which) I bought yesterday. 它是我昨天买的书。(本句是对What is that?问句的回答，that所引导的是定语从句，that可被省略)

　　It was the English book that I bought yesterday. 昨天我所卖的就是这本书。(本句相当于对I bought the English book yesterday中an English book进行强调)

　　(2) It was a room where we used to have meetings. 它是我们过去常在开会的房子。(where 所引导的从句对前面的room进行说明，它是定语从句 www.yingyuyufa.com)

　　It was in the room that we used to have meetings. 过去我们开会就在这间房子里。(in the room是被强调的部分，本句是强调句型)

　　(3) It is a day when the people celebrate their victory. 这是人们庆祝他们的胜利的日子。 (when所引导的从句对a day进行说明，是定语从句)

　　It was on that day that people celebrated their victory. 就在那一天，人们庆祝了他们的胜利。(强调on October 1, 1949)

　　3.强调句与状语从句的比较

　　◎状语从句句首的It本身就是句子的主语;而强调句首的It不作任何成分也没有实际意义。

　　◎状语从句的连接副词that及句子前面的It be不能去掉。

　　◎状语从句的引导词可以是when / where，而强调句型中的that不能用其他词代替。如：

　　(1) It is such an interesting book that we all like it very much. 它是一本如此有趣的书，我们大家都非常喜欢。(结果状语主从复合句)

　　It is such an interesting book that we all like very much. 我们大家都非常喜欢的就是一本如此有趣的书。(强调such an interesting book)

　　(比较：It is such an interesting book as we all like very much. 这就是我们大家都非常喜欢的如此有趣的书。定语从句)

　　(2) It was already morning when he woke up. 当他醒来时，已经是早晨了。(时间主从复合句)

　　It was the next morning that he woke up. 就在第二天早晨他醒来了。(强调the next morning)