InthenortheasternUnitedStates,itrainsintermittently间歇地throughoutthespring.
Thefirstpaperwasmadefromthebarkofthemulberrytree.
In1861itseemedinevitablethattheSouthernstateswouldbreakawayfromtheUnion.
Theflowerbudofawaterlily百合opensatsunsetsince.itsopeningistriggered(commence).bythedecreasedlight.
Solidgeometryhasenabledastronomerstocalculatethepositionsoftheheavenlybodiesrelativetooneanother.
AlthoughtheCarbon14methodofdatingoldobjectsisnotfoolproof,itisthebestmethodavailableatpresent