A、uFo is A gEnErAl tErm usED For Any "uniDEntiFiED Flying oBjECt" in thE sky whiCh CAnnot BE (1) By An oBsErvEr. most uFos rEmAin (2) As so EvEn AFtEr thEy hAvE BEEn invEstigAtED、thE uFo phEnomEnon DAtEs BACk (3) thE BEginning oF rECorDED history, But uFo sightings hAvE (4) inCrEAsED sinCE thE miD 1940s.
From uFo viDEos to uFo piCturEs, storiEs AnD othEr rEAl liFE (5) , thousAnDs oF pEoplE From All (6) oF liFE ClAim to hAvE sEEn thEsE mystErious AEriAl phAntoms. mAny uFo sightings turn out to BE nothing At All, mErE AirplAnEs, mEtEors or ComEts; (7) mAny sightings hAvE gonE unsolvED For DECADEs or EvEn CEnturiEs.
thE tErm "Flying sAuCEr" CAmE into (8) usE AFtErAmEriCAn kEnnEthArnolD ClAimED A uFo sighting on junE 24, 1947 nEAr mount rAiniEr, wAshington.ArnolD ClAimED to hAvE sEEn As mAny As ninE Brightly lit oBjECts soAring (9) thE sky (10) hE EstimAtED As up to 1,200 milEs pEr hour.ArnolD Also rEportED thAt thE oBjECts AppEArED to hAvE A DisC or "sAuCEr" (11) . (12) FinAl ConClusion hAs EvEr BEEn rEAChED in thE CAsE.
onE oF thE most FAmous liFo inCiDEnts to DAtE Also oCCurrED in 1947 in roswEll, nEw mExiCo. (13) uniDEntiFiED DEBris wAs rECovErED From thE (14) oF A roswEll rAnCh, thE roswEllArmyAirFiElD (15) A stAtEmEnt sAying thAt A "Flying Disk" hAD BEEn DisCovErED、thE AirFiElD (16) thE stAtEmEnt just hours lAtEr, ClAiming it wAs just A wEAthEr BAlloon. this spArkED (17) AnD nAtion-wiDE rumors oF An AllEgED govErnmEnt (18) oF An AliEn liFo thAt hAD CrAshED in thE nEw mExiCo DEsErt. no (19) prooF hAs BEEn proDuCED to this DAy to (20) thAt thEory.
A、As long AsB、so FAr
C、As FAr As D、so long