OG21的知识点总结

Feelun

       刷了一遍OG21, 总结了一下自己收集的语法知识，希望自己可以内化这些知识点，真正变成自己可以用的东西！加油

• 平行 - from ...to...
• 修饰，尤其是介词短语的修饰，要格外小心 - modifier move anround could change the logical meaning；比如OG 21中825题&925题&970，suggesting to investors the central bank in the near future is not lowering interest rate和suggesting to investors that the central bank would not lowering interest rate in the near future.
• marker - because，while，although句子要有后半句
• 时态问题 - OG21 - 839 - by 2002, 在2002之前，如果是in 2002，还可以考虑have done即现在完成时，但是by 2002要用过去时
• fear of和fear that的区别 - OG21 - 842 - fears what？如果是of 加名词，代表这个fear已经是既成事实，已经insufficient，但是其实这个预测是说有可能，即应该用从句来表达这个害怕的可能性发生；
• 平行问题 - OG - 860 - what he knows and who spoke to him --> parallel (two 'words that suggest questions' as explained above) what he knows and the people who spoke to him --> nope; the things he knows and who spoke to him --> nope; the things he knows and the people who spoke to him --> parallel (two normal nouns)
• Able和enable的用法（区别于can） - Enable--- same meaning implication as ABLE；something ENABLE people to hear certain sounds---Make sense；Something ENABLES sounds to be heard by people---NONSENSE.
• that从句后面表达的是一件事 - OG21 - 866 - 第一，要明白到底是show them walking还是show that they walked with their feet directly under their body；第二，要明白they指代谁，或者说所指代的对象可以被指代吗？第三，as这里做对比，和that从句里的dinosaur作对比，但是我有个疑惑，就是句子里用了do，在时态上walked上，do可以这么用吗？ （OG21-851就有这个选项，用时态排除了B）
• although这种带有转折逻辑的，要注意句子所要表达的meaning，到底是谁和谁做了对比，到底有没有可对比性
• so the only valid comparison is "item X is lighter than item Y". be sure that you understand why the following are correct/incorrect: ron, who weighs 215 pounds, is heavier than his brother. --> CORRECT；ron weighs 215 pounds, which is heavier than his brother. --> INCORRECT (pounds don't "weigh" anything; ron does)；ron's weight of 215 pounds is greater than his brother's weight. --> CORRECT
  

       car X is faster than car Y. --> CORRECT；the speed of car X was faster than the  
        speed of  car Y. --> INCORRECT (a speed can't be fast, although a car can be fast)；the
       speed of car X was greater than the speed of car Y. --> CORRECT

• less than不可数，fewer than可数；as many as; beween和among；not so much...as与其说，不如说
• by开头，要小心后面的主语要能够支配by,类似的还有through
• 注意with所造成的歧义，with就近修饰，且没有什么逻辑意义 - OG21 - 875&908 - 这里的with就造成歧义，好似说小飞机多飞20%的hour能够造成多hire pilot，而其实是终结小飞机多飞的20%hour，造成了多hire pilot
• if you say "when X, Y" it must actually be true that "y" when “X”
• double可以是动词也可以是副词，twice是副词，twofold是形容词或者副词：The consumption of chicken doubled to 40 grams；The consumption of chicken was 40 grams, double (or twice) （表限定）that of beef. twice as much（many）as ;无twice more than一说
• attribute sth to doing/sth
• General rule with certainty - If sophie  eats pizza, then she becomes ill.
  

           General rule with some uncertainty - if sophie eats pizza, then she may/(can)
           become ill.
          Particular case in the future with certainty - if sophie eats pizza tomorrow, then she
           will become ill.
           Unlikely case in the future - if sophie ate pizza tomorrow, then she would/(could)  
           become ill. (conditional tense) - were (if sophie were to eat pizza, she would become  
           ill.)
           Case that never happened in the past - if sophie had eaten pizza yesterday, then she   
           would have become ill.

• OG21-888 - If you predict an event, you say that it will happen; The economist predicted the recession." -✅ A "recession" is something that can be predicted "The football player predicted victory." - ✅Again, "victory" is something that can be predicted "The economist predicted the budget." - ❌what does that mean? The economist predicted that a budget would come into existence?? Without additional context, a "budget" isn't really something that, by itself, can be predicted. "The economist predicted the budget TO BE $10 million." - ✅This is much better. It probably doesn't make sense to predict "a budget", but it makes perfect sense to predict a budget TO BE some amount. You can say that the gap was predicted TO BE $2.7 billion. But you couldn't say that the gap was predicted $2.7 billion - clearly we need the ""to be"".
  

        similar in choice (C).
       对✅ ""...they believe the gap will be $3.7 billion, a billion dollars more than [the gap] was
       predicted TO BE just two months ago.""
       错❌ ""...they believe the gap will be $3.7 billion, a billion dollars more than [the gap] was  
       predicted just two months ago.""
       It makes sense to compare the gap to what the gap was predicted TO BE. But it does not  
       make sense to compare the gap to what the gap was PREDICTED.

• ONLY的用法，附上babybear姐姐的想法 - https://forum.chasedream.com/forum.php?mod=viewthread&tid=656708&highlight=only%E7%9A%84%E7%94%A8%E6%B3%95
• could have done - 过去本可以做，但是没做，也涉及到了时态
• OG21 - 892 - GMAT句子好像一个艺术作品，E完美对称，在句子结构上完美
• OG21 - 896 - A中evidence has  been gathered by scientists suggesting  that..小心-ing形式的修饰问题，这里面suggest到底是evidence还是scientist？同理，of + n. + doing这种形式也会有歧义（OG21 - 918）
• plan to do - action, 比如 i plan to take GMAT test; plan for是goal， purpose，比如 my plan for going to LBS is to take GMAT test.
• 独立主格 - A few GMAT sentences use a sophisticated modifier called an absolute phrase. Absolute phrases are composed of a noun plus a noun modifier. These phrases do not have to modify what they touch; rather, they modify the main clause in some way.
• so adj. as to和so...that的用法 - in general, you don't use so ADJ as to VERB unless the VERB describes some sort of state/condition. i.e., if the verb is an action verb, this construction generally isn't used.
  

       for instance, i am so ugly as to be viscerally repulsive to women. --> this works, because
       the verb "to be" describes a state/condition. i am so ugly as to repel women on sight. -->
       you generally wouldn't see this in good writing, as "repel" is an action verb; the sentence
       would probably be written as i am so ugly that i repel women on sight.

• OG21 - 899 - When we use the to+verb combination, it implies intention. This means that when we say the sand wants "to acquire" the characteristics of water, it is a thinking, breathing, intentional being that chooses to go out and get the characteristics of water. We know that sand isn't a living thing that has intentions of its own. Therefore, it isn't appropriate to say "to acquire." Here are some examples:
  

       I want to acquire the rights to that song for my movie. = CORRECT (I'm a person with  
        thoughts and intentions, so it's okay.)
       The chair is so short as to acquire the perfect balance for short children. = WRONG   
        (A chair can't want "to acquire" balance from somewhere - it's either balanced or it's not.
       The chair can't decide for itself what it wants to be!)
        The school acquires new students every fall. = CORRECT (Just saying "acquires"
        doesn't imply intention is involved. It just happens, so it's okay.)

• OG21 - 902 - as much as...这里有歧义，比如是knowledge inform style和inform content一样？还是说knowledge inform style 和 content inform style一样？
• in spite of + n./ despite + n. 不要加句子
• since = a continuing duration relative to the time of an earlier event(现在完成时态的标志)；after = give a time of a single event relative to an earlier point in time
• Be to do - 必须；有表示将来；也许等意义
• OG21 - 910 - 论the的重要性；同时A属于独立主格形式，如前面所述，独立主格是对主句一个补充，但是显然和句子要表达的意思不符合
• OG21 - 911 - 注意that的成分问题，比如B选项，that变成了move的宾语，不符合逻辑
• OG21 - 912 - B选项中，in addition to 在句子中，前无逗号，后有逗号，造成句子割裂成fragment；Ron提到过，modifier两边的符号要对称，比如前有逗号，后面就有逗号，前没有逗号，后面就不要有逗号，否则会造成句子fragment；
• as opposed to， unlike做对比的时候，要考虑到是说A没有这个属性，而B有；注意like所表示的逻辑，以及修饰的歧义性；similar to无法和like一样承担对比的职责，只是说一个东西和另一个东西相似，至于是哪方面相似，不得而知
• Gas prices were higher in 2007 than those in 1997 错
  

          Gas prices in 2007 were higher than those in 1997 对
          Gas prices were higher in 2007 than in 1997 对

• and是平行的marker，要看时态，形式，以及逻辑是否都平行，总之有and，but之类的要多留意，甚至是未划线的部分都不能放过
• OG21 - 929 - needle layer和layer of the needles - layer is composed of needles rather than being; procect the buds from which new growth proceeds. Proceed from 是出发，是说保护从bud里面新长出来的new growth
• X is to Y what A is to B；Air is to us what water is to fish
• The two boys are very similar.这两个男孩长得很像。你不能说，the boy is very similar
• be scheduled to do sth计划做某事
• OG21 - 942 - verb-ing这种形式做状语的时候，小心有that从句在里面混淆视听，比如verb-ing的主语到底是是谁？而且that本身可以跳跃修饰，这也是一个考点；同时that从句在like，as引导的对比中，也可以对比
• if you write “as big as X”, then X must be the actual thing whose size is under consideration. for instance, “as big as a truck” makes sense, but “as big as the size of a truck” doesn't (since the size doesn't have a size).
  

        same is true for "faster than the speed of...", "taller than the height of...", etc. -- all   
        wrong, for either of these two reasons

• 其实，有时候选项可能没有语法错误，没有逻辑错误，只是看谁更简洁而已
• “Instead of” vs “rather than” – It looks like “instead of” is used more for nouns, also has a “preference” feel to it. – “Rather than” used more for verbs.
• "to ___" —> same timeframe as the larger sentence/context in which it appears
  

       "to have ___ed" —> earlier than the timeframe of the larger sentence/context
       E.g., You appear to be injured. (It seems that you're injured right now.)
       vs.
      You appear to have been injured at work. (You may still be hurt; you may be OK now. The  
       injury happened earlier.)

• if是主动语态，then主动语态；是被动语态，被动语态
• not just …but also…不仅仅是，而且是…
• being在表示被动含义的时候，是不能省略的，一般是跟在介词后面的，比如from, with/without, for, before....
  

        being在接一个短语，在剧中承担名词性成分的时候，（直白的说就是主语，我记得做过两题
        都是在主语部分出现being），这个也是正确的。(宾语是否可以未知)
        如果being在句首，表伴随什么的，肯定不对，比如being + adj/现分/过分,being肯定多余
       结论：如果being在句中有含义的(表被动/承担具体成分)，那一定不能省略；如果去掉/留着都
        可以的，不影响表达含义的，那一定多余了。

• 做题的时候，如果你选了一个答案中有pronoun的，你一定要能找到并且清楚的指出这个pronoun所代表的名词；pronoun没有absolute rule, 唯一要注意的一个是单复数，一个是是否有这个名词存在
• OG21 - 969 句子结构 - 这道题再次体现出GMAT的beauty，比如你看结构，就会发现到底在对比什么，比如未划线的句子说a tool for communicating with large， public audience，那么前半句的主句就可以是a tool for private conversation，与之完美对应；在做题的时候，发现了一些类似的，可以总结一下以便帮助自己快速排除一些选项
• OG21 - 972 - Noun modifier Placement - 谓语特别短的时候，名词从句可以远离所修饰的名词
• If you say "in contrast to", then you don't HAVE to mention both statistics... Although you still can mention.（表示一种转折，一种相反情况的对比）
  

       Examples: "In contrast to the corresponding rate in Esteria, the unemployment rate
        in Burdistan fell last month." --CORRECT! In this case, the "in contrast to"
       construction implies that the Esterian rate went up. We don't actually have to say
       this explicitly. But, if you want, you can mention both statistics: "In contrast to the
       corresponding rate in Esteria, which rose by 0.5%, the unemployment rate in Burdistan fell
      by 0.3% last month." -- ALSO CORRECT!

• If you say "compared with/to" for statistics, you should cite BOTH statistics in the comparison. The expression "compared to/with" does NOT imply any sort of direction to the comparison; i.e., it gives no hint as to greater/less/like/unlike. Therefore, you need to give both of the relevant statistics, or else the statement won't make any sense. Examples: "The unemployment rate in Esteria last month was 5.3%, compared to the rate in Burdistan." -- INCORRECT! This makes no sense. We have absolutely no idea what is going on with the rate in Burdistan. "The unemployment rate in Esteria last month was 5.3%, compared to a rate of 7% in Burdistan." -- CORRECT! Both statistics are cited.
• 比较 - OG21 - 975 - Generally, SUBJECT + FORM OF TO HAVE + COMPARATIVE should not be followed that or those. Incorrect: The company had higher profits in 1990 than those in 1980. Correct: The company had higher profits in 1990 than in 1980.注意下面这个句子和SUBJECT + FORM OF TO HAVE + COMPARATIVE should not be followed that or those不符，In addition to having more protein than wheat does, rice has protein of higher quality than that in wheat, with more of the amino acids essential to the human diet.
• 比较 - in general, 1 * if you have than/as + subject + FORM OF "TO BE" as the second half of a comparison, then you must have another form of "to be" in the first half of the comparison. or, there should be something in the first half that would make sense with "to be" in front of it. 2 * if you have than/as + subject + HELPING VERB as the second half of a comparison, you can have just about any other form of the same verb in the first part, as determined by context. 3 * if you have than/as + subject + FORM OF "TO DO" as the second half of a comparison, then you must have an ACTION VERB (or another form of "to do") in the first half of the comparison.
  

        here are some examples: #1 the air quality of las vegas is higher this year than it was in
       2005.. also，parking spots are disappearing much more quickly today than they were
       yesterday. #2 james can negotiate with salespeople more effectively than stephanie can.
       (comparing their abilities) james can negotiate with salespeople more effectively than he
       does. (his ability exceeds his actual performance, probably because he just isn't trying
       very hard) #3 parking spots disappeared much faster today than they did yesterday.
       tanya eats more slowly than she did when she was a teenager. (note that "did" doesn't
       have to have the same tense as the action verb)

• 若出现not only，则其身后必须出现but also/but/also才能体现递进关系。
• GMAT中时态是逻辑问题，不是语法问题
  

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