InthenortheasternUnitedStates,itrainsintermittently间歇地throughoutthespring.
A、steadilySomeseaurchins海胆havevenomous(toxin)spines
Themegaphone(microphone)makesthevoicesoundlouderbecauseitpointssoundwavesinonedirectionandkeepsthemfromspreadingoutinalldirections.
Thecontrolsofmostmodernairplanescanbeoperatedeithermanuallyorautomatically.
Oneofthegreatestbreakthroughsforprofessionalwomencamein1973whenthefieldofbankingopenedupforthem.
Whencarbonisaddedtoironintheproperproportions,theresultissteel.
