Medium tractor harrows are heavier,with teeth 5/8 insquare, and are used for such purposes as the preparatiorof seed-beds, mixing of fertilizers with the soil, and sprin?cuitivation of autumn-sown corn,Thewider the implementthe more essential it is to have adequate arrangements fotransport@. For example, a 27 ft. implement designed foses,usewith tractors of 55-65B.h.p.hasthewings foldeoeds,to a transport width well under 14 ft.by a single-acting[anyhydraulic ram,controlled independently of thetractor linkdif-age. The frame may be designed to take light, mediunthator heavy sections.Drag (or duckfoot)harrows are aheavoftype of zig-zag harrow with long, curved teeth.The pointsbyof the teeth may be either chisel or "duckfoot" shapedallyThe teeth are up to 10 in.long and 3/4 in, square, and insome conditions the draught is extremely heavy. These imose-plements do much the same work as cultivators,Thein.have tended to become obsolete since effective spring-tinethecultivator-harrows were introduced. The best spring-tinellowcultivator-harrows are much more easily adjusted to do tharedepth and type of work desired, and are generally preferfinered because of their versatility.of120Words and Expressionsasilyharrow["haerau]n.粑vt.靶地pasture["pa:stJa]n.收草，收场arewidely-differing ['waidli-'difrig] employ[im'ploi]vt.用，使用di-大不相同的variety[va'raietiln.种类，项目agreat～of各种各样的zig-zag['zigzeg]a.Z（之)字飛的，Z型的suchas例如isaframe[freim]n.架seed[si:d] n.种子con-~bed苗床，种床rigid['ridsid]a.性的，坚硬的，不steddestruction[dis'trakfon]n.消灭易弯的aeration[rcia'reifon]n.通风，通气range[reinds]n，归类，分类，花13
围Vi.（在一定范内）变动、变化置，设备，安排specify'spesifai]v.规定，确定transport["trensport]n.运输reference["refrons]n.多考B.b.pBritishhorse power 英制by~to参考（照，看），根据马力bickness['eiknis】n厚（度；粗wing[win]n.（把)翼(细)fold[fould]v.折登owing["ouin]to由于single-acting ['singl-taektin] a. 单stagger【'steega】vi.交错（配置）；铬作用的开ram[raem]n.油缸track[trak】n，轨迹，印速，齿沟independently[indi'pendantli]ad.front[frant]a.前面的，前部的n独立地，单独地前面，前部～与无美地，不受·支drin[dril]n.条播机：播种（条插）配地available[3rveilobl]a.可用的，合medium['mi:djom]a.中等的，中用的；可得到的闻的～for适用于.的section【'sekJan]n，（把）组，一段，capacity[ko'paesiti]n.能力，能量;一部分drag[draeg】n：拖（克），牵引（式的）容量，容积frequently[fri:kwentli]ad.经常~harrow宽齿靶地，频繁地suckfoof['dakfut]a.鸭掌形的hiteb[hitvt.联结（挂结，悬挂）cured['kervd]a.湾曲的handy["haendi]a.灵巧的chisel["tjiz]n.酱子device[di'vais]】n.装置，设备，器draught[draift]n.牵引（阻）力械（件，具）extremely[ilcs'trirmli]ad.极度地，manufacturerLmenju'faktfaro]n.极端地制造商；制造广obsolete["obsalit]a.陈旧的，已不row[rou]n.（—)排(—)行用的coverer["kavaro]n.爱土器spring-tined ['sprig-taind]a.弹齿sait[sju:t，suit]vi.适合的autumnsown[otomsoun]a.秋播～cultivator-harrow弹齿深松土的中耕机corm[kor]n.【英］谷物；美、加拿introduce[intra'djurs]yt.推广，采大、澳大利亚门玉米用介绍essential[i'senfol]a.基本的，必要prefer[prifo:]vt.宁愿（选择），更的喜欢adequate['edikwit]a.适当的；足versatility[versa'tilitil n.通用性，够的多面性，多方面的适应性arrangement[a'reindsmant]n.装14
ENotes英制①thatwitha zig-zagiron frame and rigidteeth:具有z形铁架和刚齿的把。that代表type，介词短语with.teeth作定语，修饰that。so that those at thereardo not follow in the tracks of the front②a.单ones:从而使后齿不致重靶前齿的齿沟。sothat引导结果状语从句those和ones均为代调，代表teeth。?areeasilywithinthecapacityof smallmachines:用小型拖拉机就可i]ad.以胜任自如。machines在此代表施拉机。The wider the implement, the more essential it is to have adequate④支arrangementsfortransport，这是一个主从复合句，前一分句为比较状语从句，其中theimplement（代表harrow)为主语，其后省略了系词is，th的，中wider为表语；后一分句为主句，其中it为形式主语，实际主语为不定式短语tohave-adequatearrangements...themoreessential为表语。全一段，句可译为：靶越宽，就越需要有合适的运输安排。(式的) a 27 ft. implement designed for use...controlled independently othetrauctorlinkage:句中分调短语foldedto...ram修饰wings;con彩的trolledindependenilyof...修饰ram；well在此意为“大大，很”，welunder...意为“远不到（低于）..."。全句可译为：设计与55-65英制马力的拖拉机配套的27英尺宽的靶，其靶翼可借助单作用液压缸折叠成运)力不到14英尺的运输宽度，此液压缸单独控制，与拖拉机悬挂装置无关。极度地，Theseimplementsdomuchthe samework ascultivators.中?cultivators相当于as cultivators do。全句可译为：这种靶进行的作业的，已不和(一般的)耕耘机的极为相同。The:best spring-tined cultivator-harrows aro much more easily ad7.弹齿①justedto dothedepthandtypeof workdesired:最好的弹齿深松中机调整起来容易得多，可以满足所需的深度和作业要求。muchmo深松士easily意为“容易得多”不定式短语to do..desired作结果状语，修推广，采adjusted,择），更通用性
4,GRAINDRILLSGrain drills are very versatile and can be used for awide range of seeding work. In essence a grain drill con-sists of a hopper to hold the seed, a metering and feedingdevice beneath the hopper, connected to the coulter tubes,and planting and covering mechanism. The number of coul.ters varies with the size of the drill. The sowing width ofa drill is the number of coulters multiplied by the distancebetween them.HopperDrive shaftPiainrollerFluted rollerTo coulter tubeFig.3.ExternalForceFeedA common metering device is the external force feed(Fig. 3). This consists of a roller, part of which is fluted,rotating in a housing below the hopper@.Grain is carried16
from the hopper to the coulter tubes between the flutes oithe roller@. An adjustable flap may be fitted round partof the circumference of the roller, to permit different sizesof seed to be sown. The seeding rate is controlled bythe amount of fluted roller exposed in the housing. Theremainder of the space is occupied by the plain section offoraroller.If the maximum length of flute does not produce con-suficiently heavy sowing rate, the speed of the fluted rolleedinger can be increased by changing sprockets or gears in thetubes,drive.fcoul-dthofistanceHoppeFlapDisCastingFlutedinternaledgeof flangeftCoultertubeefeedFig.4.Internal ForceFeedfluted,The internal force feed mechanism consists of a seriecarried1