AlthoughtheCarbon14methodofdatingoldobjectsisnotfoolproof,itisthebestmethodavailableatpresent

InthenortheasternUnitedStates,itrainsintermittently间歇地throughoutthespring.

Formerly , in the United States, many nurses worked as private duty nurses rather than in hospitals.

Amythical(imaginary)creature,thedragonwasbelievedtohavelion'sclaws,scalyskin,andfierybreath.

Alllivingorganisms,regardlessoftheiruniqueidentity,havecertainbiological,chemical,andphysicalcharacteristicsincommon.