3. Readthearticleagaincarefullyandworkoutthequestionstothegivenanswers.

1. Intheearly1830s.

2. Afterbeingadapted.

3. 551tons.d)£350,000.

5. Becausepickingapplesisverydifferenttopluckingstrawberries.

6. ByJapan’sNationalAgriculturalResearchCentre.

4. Translatethelastparagraphofthearticleinwrittenform.

5. SkimthefollowingarticletofindthesentenceswiththeGerundsandstatetheirfunctions. Metal,healthyself

AwayforthedamagedsurfacesofmetalstorepairthemselveshasbeendevisedSadlyforengineers,inanimateobjectscannotyetrepairthemselves.Butscientistshaveinventedawayofhealingdamagedmetals.

Thesurfacesofmanymetalobjectsarecoatedwithothermetalsforprotection.Iron,forinstance,isfrequentlygalvanizedwithzinc.Thebasicideaofthenewtechnologyistoinfiltratethiscoatingwithtiny,

fluid-filledcapsules.Whenthemetalcoatingispuncturedorscratched,thecapsulesinthedamagedareaburstandoozerestorativeliquids,intheformofcompoundscalledtrivalentchromates.Thesereactwithnearbymetalatomsandformtough,protectivefilmsafewmoleculesthicktoamelioratethedamage.

Theideaofdoingthishasbeenaroundforyears,butithasproveddifficultinpracticebecausethecapsulesusedweretoobig.Surfacecoatingstendtobeabout20micronsthick.Thecapsuleswere10-15micronsacross-largeenoughtodisruptthecoatings,andthusdomoreharmthangood.Thetrickworkedoutbyscientistsishowtocreatecapsulesafewhundredthsofthissize.

Thecapsulesresearchershavecomeupwitharemadebymixing

butylcyanoacrylate,achemicalfoundinsuperglue,withanoilcarryingthehealingcompounds.Thismixtureisthen,itself,mixedwithdilutehydrochloricacid.Theresultisanemulsionofdropletsbetween100and300nanometersacross.Eachdroplethasanoilcoresurroundedbyathinlayerofbutylcyanoacrylatemolecules.Tomakethedropletsstable,phosphateisaddedtotheemulsion.Thistriggersthepolymerizationofthebutylcyanoacrylateintoatoughplastic,whichformstheoutsideofthecapsule.

Thegreatestchallenge,however,wasnotmakingthecapsulesinthefirstplace,butstabilizingthemduringtheplatingprocess.Thoughgalvanizationisoftendonebydippingsteelinliquidzinc,itissometimesdonebyelectrolysis-andnickelandcopperplatingarenormallydonethisway.Thecapsules,though,tendtosticktogetherintheliquidsusedaselectrolytesduringelectroplating,andarealsodestroyedbytheextremeacidityoralkalinitythatisofteninvolvedintheprocess.Toovercometheseproblemsspecialdetergentsthatsticktopolybutylcyanoacrylatewereused,andthusbothstopthecapsulesstickingtogetherandprotectthemfromtheelectrolytes.Thetechniqueswereprovedinelectroplatedlayersofcopper,nickel,andzinc,andself-repairingmetalsarebelievedtocommonlybeavailableintheyearsahead.

TheEconomist

6. Readthetextagainandmatchtheitalicizedwordsandwordcombinationswiththeirmeanings.

1. ___________________ataskorsituationthattestssomeone'sabilities

2. _____ ______acleansingagent,esp.asurface-activechemical suchasanalkylsulphonate,widelyusedinindustry

3. ___________________ to think of a plan or idea and suggest it

d)___________________tohavegainedknowledgeandexperienceoftheworld

5. ___________________restore(somethingdamaged,faulty,orworn)toagoodcondition

6. ___________________lackingthequalitiesorfeaturesoflivingbeings

7. _____ _asubstanceformedfromtwoormoreelementschemicallyunitedinfixedproportions

h)__________________tomakeorbecomebetter;improve