InthenortheasternUnitedStates,itrainsintermittently间歇地throughoutthespring.
Withlasersscientistscanprobemanyphysicalprocesses,suchascombustion,oncebeyondourken.视野
Somechildrendisplayanunquenchable难以抑制的curiosityabouteverynewthingtheyencounter.
Formerly,intheUnitedStates,manynursesworkedasprivatedutynursesratherthaninhospitals.
Alllivingorganisms,regardlessoftheiruniqueidentity,havecertainbiological,chemical,andphysicalcharacteristicsincommon.