Structure 句型Lesson 15 in some part of the world people are still_b_ to write A incapable b impotent c enable d unable6 they can preserve their history _d_ down legendsA by hand b by handing c to hand d in hand7the _a_ why these legends are useful is that they tell us about migrationsA cause b effect c why d reason8 there werent _a_ of then who could write down what they did.A any b none c no one d noLesson 25 it would _a_ impossible for us to live in this world if insects had no enemies.A make it b stay c be d have it 6 we owe _c_ to the birds and beast who eat insects.A a great deal b a lot of c a great many d much of7 how many spiders are involved _a_ this work on our behalf?A at b for c in d to 8 there are many different _a_ spidersA sort of b kind of c type of d kindsLesson 35 earlier climbers liked summits _c_ had never been climbed before.A which b which they c that they d unless they 6 _d_ single aim was getting to the topA theyre b there c their d theirs7 _a_ Zermatt and Chamonix,most places were unknown.A except b unless c without d apart from8 _b_ were generally dirty and flea-ridden.A the few inns that existed b inns like this C such inns d few innsLesson 45 several cases have been reported in Russia recently of people _b_ can readA whom b that c which d they 6 one day she came into his office and put her hands on the door of the safe _c_ A as it happened b by chance c perhaps d intentionally7 _d_ these tests were being conducted ,she was able to read a newspaper.A during b on occasion c while d as if8 Vera couldnt see with her skin _a_ she was blindfold .A only b except c as if d unlessLesson 55 the problem,if there is one, _d_ by older peopleA created b is created c creates d is creating6 for one thing ,if you _a_ a problem,you have a certain identity.A were b being c had d are 7 _c_ to be linked with life ,and the origin of things.A they seem b it seems c this seems d what seems 8 it is _b_ they are conceited and ill-manneredA necessary b permissible c possible d likely Lesson 65 if only _a_ possible for the common people to meet each other.A it would be b it could be c it were d it might be 6 you play _a_ win A in order to b in order that c so that d for 7 the village green is the _a_ you pick sides.A the place b the time c the reason d the cause8 _d_ the question of national prestige arisesA the moment b just c as long as d provedingLesson 75 not _b_ sound made by animals serves as languageA every b each c the whole d the entire6 we have only to turn to that extraordinary discovery of echo-location in bats to see a case _a_ the voice plays a strictly utilitarian roleA which b where c when d though7 _c_ he shout in the vicinity of a wall, an echo will come back.A should b if c when d though8 _d_ the echo-sounding apparatus was born.A such b the way c thats how d like thisLesson 8 5 american farmers cant export chickens to europe _b_ differences in national regulations.A through b according to c in respect of d because of 6 an electric razor from the eu _a_ sold in the us unless it meets us standards.A oughtnt to be b cant be c shouldnt be d doesnt have to be 7 america and the eu _a_ to reach a deal A are still trying b slways try c tried d were trying8 the details are _b_ that they may be hard-pressed to get a deal.A so complex b enough complex c such complexity d too complex