问题标题:
【Readingcomprehension.Theoldbeliefthattheuniverseneverchangesisquitewrong.Evenbeforetheinventionofthetelescopeastronomersnoticedthatbrightstarssuddenlyappearedintheskyandthenlaterdisappeared.Thesestars】
问题描述:

Readingcomprehension.

Theoldbeliefthattheuniverseneverchangesisquitewrong.Evenbeforetheinventionofthetelescope

astronomersnoticedthatbrightstarssuddenlyappearedintheskyandthenlaterdisappeared.Thesestars

werecalled"novae"becausetheywerethoughttobenew.Infactwenowknowthattheyarereallyoldstars

whichareslowlydying.

Novaeareoldstarswhichareslowlydying.Astheydosotheyletouthugecloudsofmaterialsometimes

aslargeastheearthandtheseexplodeintospaceataspeedofabout8000000kilometersperhour.When

thishappensthehotterpartsofthestarbecomevisibleandthisiswhynovaearesobright.Althoughthe

explosionsaresohugeonahumanscaletheyonlyconsumeasmallpartofthedyingstar'senergy.Thedeath

isaslowoneandthestarmaycontinuetoexplodeforthousandsofyears.Indeedthereareevensomestars

whichexplodeonceeverytwoweeks.

Thereareotheroldstarswhichdonotdieslowlybutarecompletelydestroyedbyonegreatexplosion.

Theseareknownas"supernovae".Theexplosionofasupernovaeisequivalenttoaboutamillionmillion

millionmillionhydrogenbombsgoingoffatthesametime.Justbeforetheexplosionthestar'sdensitybecomes

verygreatanditspinsataveryhighspeed.Amatchboxofmaterialstakenfromthestaratthattimewould

weighabout1000tonsandthestarwouldbeturningatabout16000000kilometersperhour.Theexplosion

itselfoccurssuddenlyintheintervalofaminutebutthesupernovaecontinuestoshinelongaftertheevent.

OnesupernovaewhichChineseastronomersobservedin1054canstillbeseenbyustoday.Ithasbeenshining

foratleastninehundredyears.

1.Novaewereoriginallythoughttobe_____.

A.starsthatdisappearsuddenly

B.starsthatexplode

C.newstars

D.dyingstars

2.Supernovaearedifferentfromnovaebecause_____.

A.theyaredyingstars

B.theydiegradually

C.theycanbeseenfromtheearth

D.theyexplodesuddenly

3."Astheydoso"(line1Paragraph2)means_____.

侯本涛回答:
  1-5CDBCB
查看更多
八字精批 八字合婚 八字起名 八字财运 2024运势 测终身运 姓名详批 结婚吉日
已出生未出生
英语推荐
热门英语推荐
付费后即可复制当前文章
《【Readingcomprehension.Theoldbeliefthattheuniverseneverchangesisquitewrong.Evenbeforetheinventionofthetelescopeastronomersnoticedthatbrightstarssuddenlyappearedintheskyandthenlaterdisappeared.Thesestars】|小学英语问答-字典翻译问答网》
限时特价:5.99元/篇原价:20元