1、Chapter 7 Verb Tense, Mood note that the future will is often dropped in subordinate clauses.)Right: She will pay you when you have taken out the garbage.(The time of will pay is later than the future time of have taken.)Past Perfect: The Earlier ActionIf two actions in a sentence occurred at differ
2、ent times in the past, we often use the Past Perfect tense for the earlier action and Simple Past for the later action.Note that we do not always use the Past Perfect for earlier actions. In general, you should use Past Perfect only to clarify or emphasize a sequence of past events. The earlier even
3、t should somehow have a bearing on the context of the later event. Moreover, if the sequence is already obvious, we often do not need Past Perfect.Right: Antonio drove to the store and bought some ice cream.(A sequence of verbs with the same subject does not require Past Perfect. Rather, use the Sim
4、ple Past for all the verbs.)Right: Antonio drove to the store, and Cristina bought some ice cream.(In the sentence above, which has two main clauses linked by and, we are not emphasizing the order of events. Clauses linked by and or but do not require the Past Perfect as a general rule.)Right: Laura
5、 locked the deadbolt before she left for work.(Likewise, we already know that locked happens before left because of the word before. The words before and after indicate the sequence of events clearly and emphatically enough to make the use of Past Perfect unnecessary.)Also, note that the later past
6、event does not need to be expressed with a Simple Past tense verb. You could just use a date or another time reference.E.g. By 1945, the United States had been at war for several years.Using this construction, you can even make a tricky sentence in which the first clause expresses an early action in
7、 Simple Past. Then, a second clause expresses a later action in Past Perfect to indicate continued effect (by a still later past time).E.g. The bond U2 was just one of many new groups on the rock music sense in the early 1980s, but less than ten years later, U2 had fully eclipsed its early rivals in
8、 the pantheon of popular music.Perfect Tenses: Only when necessaryYou should use the perfect tenses only when you can justify them with the rules described here:If an action began in the past and continues into the present (or its effect does), use the present perfect tense. If one action in the pas
9、t precedes another, and you need to clarify or emphasize the time sequence, then use the past perfect tense. Otherwise, stick to the simpler tense.Tense SequenceAvoid mixing Present Tense with Conditional Tense. Likewise, avoid mixing Past Tense with Future Tense. The usual sequences are either Pres
10、ent+ Future or Past+ Conditional.Right: The scientists believe that the machine will be wonderful.Right: The scientists believed that the machine would be wonderful.The Subjunctive MoodVerb mood expresses what the writer believes about, or wants to do with, the action expressed by the verb. In Engli
11、sh, most sentences express facts with the Indicative Mood or commands with the Imperative Mood. You can expect to see the Subjunctive Mood in two special situations:1. Unlikely or unreal conditions (usually after if or a similar word)2. Proposals, desires, and requests formed with certain verbs and
12、the word thatThe Hypothetical SubjunctiveWe use the Hypothetical Subjunctive form in a few circumstances to indicate unlikely or unreal conditions. Principally, this form occurs after if, as if, as though.E.g. To overcome my fear of germs, I will think about disease as though it were harmless.If The
13、n ConstructionsSentences that use the word if do not always use the Hypothetical Subjunctive. Sentences with an if condition and a then can follow any of several tense/mood patterns.General Rule with no uncertaintyIf Sophie eats pizza, then she becomes ill. If present, then presentGeneral Rule with
14、some uncertaintyIf Sophie eats pizza, then she may be ill. If present, then can/mayParticular Case (in the future/ present) with no uncertaintyIf Sophie eats pizza, then she will be ill. If present, then futureIf Sophie has eaten pizza, then she will be ill. If present perfect, then futureUnlikely C
15、ase (in the future)If Sophie ate pizza tomorrow, then she would become ill.If hypothetical subjunctive, then conditionalCase that never happed (in the past)If Sophie had eaten pizza yesterday, then she would have become ill.If past perfect, then conditional presentStick to the five if then construct
16、ions. Do not use would in the if clause. Do not use should anywhere in an if then sentence.The Command SubjunctiveThe Command Subjunctive is used with certain Bossy Verbs. Bossy Verbs tell people to do things.The Subjunctive Construction with a Bossy Verb is always as follow:Bossy Verb + THAT + Subj
17、ect+ Command SubjunctiveNot every Bossy Verb uses the Command Subjunctive, some bossy verbs (such as want) cannot use the Command Subjunctive, but rather an infinitive.Common Verbs that take Only the Command Subjunctive: demand, dictate, insist, mandate, propose, recommend, request, stipulate, sugge
18、stE.g. We demand THAT he BE here.Verbs that take Only the Infinitive: advise, allow, forbid, persuade, wantE.g. We allowed him TO BE here.Verbs that take Either the Command Subjunctive Or the Infinitive: ask, beg, intend, order, prefer, urge, requireE.g. We require THAT he BE here. We require him TO
19、 BE here.A few Bossy Verbs, most notably prohibit, take other constructions altogether:The agency prohibited Gary from working on weekends.The Command Subjunctive can also be used with nouns derived from Bossy Verbs, such as a demand or a request.His demand that he be paid full severance was not net
20、.Also, the Command Subjunctive is possible with “It is X”, in which X is an adjective, such as essential, that conveys urgency.It is essential that Gary be ready before noon.Other adjectives conveying urgency include advisable, crucial, desirable, fitting, imperative, important, mandatory, necessary
21、, preferable, urgent and vital.Note that you can use an infinitive in these constructions: It is essential for Gary to be ready before noon.Active Voice vs. Passive VoiceThe passive voice is formed with a form of the verb to be, followed by the past participle. Do not use other verbs than be to form
22、 the passive voice.Wrong: The pizza got eaten by the hungry students.Right: The pizza was eaten by the hungry students.Whoever actually performs the action in the sentence may follow the verb in a phrase headed by the preposition by. Use by only for the actual doers of the action. Use through or bec
23、ause of when you want to describe any instruments or means, which might be an awkward subject in active voice.Wrong: The pizza was accidentally eaten by a quirk of fate.Wrong: A quirk of fate accidentally ate the pizza.Right: Through a quirk of fate, the pizza was accidentally eaten.Since GMAT prefe
24、rs brevity and simplicity, you should avoid answer choices written in the passive voice when the passive voice contributes to unnecessary wordiness or confusion.Only Transitive Verbs (Verbs that take direct objects) can be written in the passive voice. Verbs that do not take direct objects should ne
25、ver be written in the passive voice.Wrong: The aliens were arrived on Neptune in the 20th century.Right: The aliens arrived on Neptune in the 20th century.Is Passive Voice Ever the Correct Answer?Yes. Note that you do not have to make active or passive voice parallel throughout a sentence. However, if all other issues are solved equally well in two sentences choose the sentence that maintains parallelism of voice rather than the sentence that does not.
