1、Thecyclesofthesunandmoonaresimplebut__________forceswhichhaveshapedhumanlivessincethebeginning.
2、Greywhaleshavelongbeen__________inthenorthAtlanticandhuntingwasanimportantcauseforthat.
3、Isitpossibletostopdrug__________inthecountrywithinaveryshorttime?
4、Mainstreampro-marketeconomistsallagreethatcompetitionisan__________spurtoefficiencyandinnovation.
5、AncientGreekgymnasticstrainingprogramswereconsideredtobean__________partofthechildren'seducation.
6、Tolabeltheirproductasorganic,farmershavetoobtainacertificateshowingthatno__________chemicalshavebeenusedtokillpestsonthefarmfortwoyears.
7、WhentheItalianpoetDantewas__________fromhishomeinFlorence,hedecidedtowalkfromItalytoParistosearchfortherealmeaningoflife.
8、Variouseffortshavebeenmadeoverthecenturiestopredictearthquakes,includingobservinglightsintheskyand__________animalbehavior.
9、Fiber-opticcablescancarryhundredsoftelephoneconversations__________.
10、Itisawell-knownfactthatthecatfamily__________lionsandtigers.
11、Iwasso__________whenIusedtheautomaticcheckoutlaneinthesupermarketforthefirsttime.
12、ProfessorSmithexplainedthemovementoflight__________thatofwater.
13、Philosophersbelievethatdesire,hatredandenvyare"negativeemotions"which__________themindandleaditintoapursuitofpowerandpossessions.
14、Fashiondesignersarerarelyconcernedwithvitalthingslikewarmth,comfortand__________
15、Amongallthepublicholidays,NationalDayseemstobethemostjoyfultothepeopleofthecountry;onthatdaythewholecountryis__________inafestivalatmosphere.
16、Manymanufacturerswereaccusedofconcentratingtooheavilyoncostreduction,oftenatthe__________ofthequalityoftheirproducts.
17、Enk'swebsitecontains__________photographsandhundredsofarticlesandshortvideosfromhistriparoundtheglobe.
18、Ourresearchconfirmedthe__________thatwhenchildrenhavemanydifferentcaregivers,importantaspectsoftheirdevelopmentareliabletobeoverlooked.
19、Thepandaisanendangeredspecies,whichmeansthatitisverylikelytobecome__________withoutadequateprotection.
20、Onlineschools,which__________theneedsofdifferentpeople,haveemergedasanincreasinglypopulareducationalternative.