ThefuturesurvivalofthebaldeagleisstillanimportantAmericanecologicalconcern.
A、migrationSolidgeometryhasenabledastronomerstocalculatethepositionsoftheheavenlybodiesrelativetooneanother.
Formerly,intheUnitedStates,manynursesworkedasprivatedutynursesratherthaninhospitals.
Theflowerbudofawaterlily百合opensatsunsetsince.itsopeningistriggered(commence).bythedecreasedlight.
In1861itseemedinevitablethattheSouthernstateswouldbreakawayfromtheUnion.
Blue－greenalgaegrowabundantlyinsaltmarshes.
