Ifasubstanceisdissolvedinwaterorheated，itmay（）agas.

Passage2

Questions6to10arebasedonthefollowingpassage:

Thefoodweeatseemstohaveprofoundeffectsonourhealth.Althoughsciencehasmadeenormousstepsinmakingfoodmorefittoeat,ithas,atthesametime,mademanyfoodsunfittoeat.Someresearchhasshowntat40percentofcancerisrelatedtothedietaswell,especiallycancerofthecolon.Differentculturesatemorepronetogetcertainillnessesbecauseofthefoodthatischaracteristicinthesecultures.Thatfoodisrelatedtoillnessisnotanewdiscovery.In1945,governmentresearchersrealizedthatnitratesandnitrites,commonlyusedtopreservecolorinmeats,andotherfoodadditives,causedcancer.Yetthesecarcinogenicadditivesremaininourfood,anditbecomesmoredifficultallthetimetoknowwhichthingsonthepackaginglabelsofprocessedfoodarehelpfulorharmful.Theadditivesthatweeatarenotallsodirect.Farmersoftengivepenicillintobeefandpoultry,andbecauseofthis,penicillinhasbeenfoundinthemilkoftreatedcows.Sometimessimilardrugsareadministeredtoanimalsnotformedicinalpurposes,butforfinancialreasons.Thefarmersaresimplytryingtofattentheanimalsinordertoobtainahigherpriceonthemarket.AlthoughtheFoodandDrugAdministration(FDA)hastriedrepeatedlytocontroltheseprocedures,thepracticescontinue.

6.Howhassciencedoneadisservicetomankind?

A.Becauseofscience,mostofthefoodsweeattodayarecontaminated.

B.Ithascausedalackofinformationconcerningthevalueoffood.

C.Asaresultofscientificintervention,somepotentiallyharmfulsubstanceshasbeenaddedtoourfood.

D.Thescientistshavepreservedthecolorofmeats,butnotofvegetables.

7.Whatarenitratesusedfor?

A.Theypreservesflavorinpackagedfoods.

B.Theypreservethecolorofmeats.

C.Theyaretheobjectsofresearch.

D.Theycausetheanimalstobecomefatter.

8.TheFDAhastriedrepeatedlytocontrol.

A.theattempttofattentheanimals

B.theattempttocuresickanimals

C.theusingofdrugstoanimals

D.theusingofadditivestopreservethedoloroffood

9.Theword“carcinogenic”meansmostnearlythesameas.

A.trouble-makingB.color-retaining

C.money-savingD.cancer-causing

10.WhichofthefollowingstatementsisNOTtrue?

A.Drugsarealwaysgiventoanimalsformedicalreasons.

B.Someoftheadditivesinourfoodareaddedtothefooditselfandsomearegiventothelivinganimals.

C.Researchershaveknownaboutthepotentialhazardsofthefoodadditivesforoverthirty-fiveyears.

D.Foodmaycausefortypercentofcancerintheworld.

John'sscoreonthetestisthehighestintheclass;he____lastnight.

—Canyoutakethedayofftomorrow?

—Well，I‘allhavetoget（）frommyboss.

翻译：

如今，中国正步入老龄化社会，因此独生子女一代面临着巨大的工作和生活压力。中国政府开始适当调整计划生育政策，允许一些家庭在特殊情况下生育二胎。但调查显示，很多夫妻迫于不断加重的经济压力，放弃生育二胎。因此，要从根本上解决老龄化的问题不能依靠出生率的上升，最有效的办法是建立有效的社会保障制度。