Prefixesindicatingnegation在单词的加上一个表示含义的词缀。:dis-;il-,im-,in-,ir-;un-;non-;mis-等;:“非”、“无”、“不(是)”、“未”等。1.dis-常加在名、形、动之前。如:disagree(ment)(分歧;不赞同)discouragevt.使气馁disagreeableadj.不愉快的disadvantage(不利条件;缺点)disorder无秩序disappear(v.消失)discomfort(n.不舒适vt.使不舒适)dishonest(adj.不诚实的)dislike(v.不喜欢)但likeprep不像dissatisfactoryadj.不令人满意的但satisfieddiscovervt发现但cover揭露,暴露2.in-;il-,im-,ir-(in-在辅音n,l,m,p,r前要变体)加在形容词、名词、副词上expensiveequal不平等的correctvalid无效的different冷漠的accurate不准确的active,directvisible,credible,curablea.常加在以字母开头的形容词之前:impossible(不可能的)impolite(无礼的;粗鲁的)impatientimbalanced(adj.不平衡的)但:parallel不平行的pleasantpopularpoisonous无毒的b.il-,ir-加在和开头的形容词之前illegal(非法的)illogical(不合逻辑的)irregular(不规则)irresponsibleirrelevantilliterate不识字的irrelative无关的但:reasonable不合理的,不公道的3.un-加在形容词、副词、名词及用于作形容词的分词上unhappiness不幸福unusual不寻常的;罕见的unimportant不重要的unfriendly不友好的uncomfortable不舒服的但discomfortn/vtunsafe不安全的unwelcome不受欢迎的uncommon不常见的unaware没意识到的不舒适;使…不舒服un-用于动词之前表示做相反的动作lockv.锁,锁上lockvt.开...锁covervt.覆盖covervt.揭开,揭露foldv.折叠foldv.打开dressv.穿衣dressvt.使脱衣服loadv.装载loadv.卸货un-未(主要用于过去分词之前)expected未预料到)locked未上锁的educated未受教育的decided未决定的finished未完成的crowded不拥挤的doubted无疑的married未结婚的4.non-加在名、形、副或作形容词的分词前,表“”之意sense(n.胡说、废话)violent(adj.非暴力的)poisonous无毒的existent不存在的smoking不准吸烟的stopa.直达的5.ab-,ab-加在词根前,表示相反,离去”如:normal(ab+normal正常的)反常的abuse滥用、错误使用、虐待6.mis-加在动词、名词之前understand误解judge误判leading误导fortune不幸Exx:根据语境,用所给词的否定形式填空1.Itis________(legal)todriveafterdrinkingalcohol.酒后开车。2.___________(lead)advertisementsarenotallowedbylaw.的广告为法律所不允许。3.Itis_____________(reasonable)tosticktothisabsurdproposal.坚持这种荒谬的建议是。4.Thereexiststhe___________(balance)betweentherichandpoorcountries.富国与穷国之间存在着。5.Thegovernment________(close)thatanotherambassadorhadbeenarrestedforspying.政府另一个外交大使园间谍罪被逮捕。6.Hisidentityis________(know)toussowehavetoconfirm.他的身份我们,所以我们得证实。7.Heseemstobe________(aware)ofthetroubleheismaking.他似乎他正造成的麻烦。8.Jimis________(patient)withhislittlesisterwhoissonoisy.吉姆对他吵闹的小妹妹。9.The____________(expect)deathofhersonmadeheisad.她儿子死亡使她伤心。10.Herillnesshadmadehercompletely________(mobile).她的病使得她完全了。11.Runningabusinesswithoutabudget(预算)is________(practical).经营生意而没有预算是。12.Thebrightdressis________(proper)forafuneral.鲜艳的衣服对葬礼来说。13.Studentsgeta________(count)of25%onplanetickets.学生享有25%的机票。14.Thewateris________(fit)fordrinkingandyouhavetogowithoutwater.这水饮用,你只能不喝水了。15.Youmustbe________(literate)ifyouhavenotheardofShakespeare.如果你没听说过莎士比亚,那你一定是。16.He________(like)wearingatie,soyouwillneverseehimintie.17.___________(amaze/surprise),heshouldlosehistemperinpublic.18._____________(expect),theinjuredathletecamefirstinthe100meterdash.19.Themother__________(dress)herbabyandgaveitabath.20.Thisdelaywas__________(avoidable)sowehadtobepatient.延迟不可避免,所以我们得耐心21.Hisincomeis________(adequate)tomeethisbasicneedsandhehastofindanotherjob.他的收入不足以满足基本要求,他得再找份工作。22.It's________(honesty)tolieaboutone'sage.谎报自己的年龄是不诚实的。23.Theinjuredmanwas________(capable)ofwalking,sohehadtobecarried.那个受伤的人不能走路,所以他得被人背着。24.Hewas________(ability)tosleepatnightbecauseofhisanxiety.由于焦虑,晚上他不能入睡。25.Thefishisabit________(smell).Wecan'teatit.