请教各位几道语法改错题,错误已标出,求解释为什么错,应该改为什么,
Formostoftheirhistory,especiallysincethe1860's,NewYorkCityhasbeenundergoingmajorethnicpopulationchanges.(their)
MostofourideasofwhatancientpeoplelookedanddressedcomefromtheworksofRenaissanceartists.(what)
Allnationsmayhavetomakefundamentalchangesintheireconomic,politicalandthetechnologicalinstitutionsiftheyaretopreservetheenvironment.(thetechnologicalinstitutions)
Massachusetteswasfirstexploredinthelatesixteenthandearlyseventeenthcenturies,andthefirstpermanentsettlementatPlymouthin1620.(settlement)
SarahVaughanhadavoicelikeaperfectinstrument,anditwasaninstrumentthatsheknewhowtouseitwiththeutmostskill.(touseit)