The controls of most modern airplanes can be operated either manually or automatically.
A、bythebookD
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Urbanrenewalprogramsstrivetoupgradeareasthatarebecomingslums.
ThecompanyissuesanannualreporteveryMarch.
Solidgeometryhasenabledastronomerstocalculatethepositionsoftheheavenlybodiesrelativetooneanother.
Communicationisoneofthemostimportantbondsthatholdculturalsystemstogether.
Thefirstpaperwasmadefromthebarkofthemulberrytree.
