estimated
hesitated
It _________ be you that broke the vast.A.canB.mustC.shouldD.have to
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An audience of millions watched the wedding on TV.
SPAC系统
卡介苗的英文缩写为A、BAGB、SPAC、BCGD、SPGE、SCG
辣根过氧化物酶英文缩写是A、APSB、SPAC、IIRPD、HRPE、OPD
11． —Have you seen the CCTV news on TV?—Yes，_________ children had a good festival on the ________Children's Day．A． millions of; sixtyB． ten million; sixtyC． millions of; sixtiethD． ten millions ; sixtieth
共用题干 B1i'k Holes1 Black holes can be best described as a sort of vacuum,sucking up everything in space. Scientists have discovered that black holes come from an explosion of huge stars. Stars that are near death can no longer burn due to loss of fuel , and because its temperature can no longer control the gravitational（重力的）force, hydrogen ends up putting pressure onto the star' s surface until it suddenly explodes then collapses.2 Black holes come from stars that are made of hydrogen,other gases and a few metals. When these explode it can turn into a stellar-mass ( 恒星质量）black hole , which can only occur if the star is large enough (should be bigger than the sun) for the explosion to break it into pieces,and the gravity starts to compact every piece into the tiniest particle. Try to see and compare:if a star that' s ten times the size of the sun endsup being a black hole that' s no longer than 70 kilometers ,then the Earth would become a black hole that' sonly"fraction of an inch! 3 Objects that get sucked in a black hie will always remain there,never to brsak fren. But rememberthat black holes can only gobble up（吞噬）objects within a specific distance to it It' s possible for a largestar near the sun to become a black hole,but the sun will continue to stay in place. Orbits (轨道）do notchange because the newly formed black hole, contains exactly the same amount of mass as when it was a star,only this time its mass is totally contracted that it can end up as on biggeer tnan a state. 4 So far, astronomers have figured out that black holes exist because of Albert Einstenin's theory of relativity. In the end,through numerous studies ,they have discovered that black holes truly exist. Since blackholes trap light and do not give off light,it is nearly impossible to detect black goles via a telescope. Butastronomers continue to study galaxies (银河系）,space and the solar system to understand how black holes misht evolve. It is possible that black holes can exist for millions of years,and later contribute to a biggerprocess in galaxies ,which can eventually lead to creation of new entities（实体）.Scientists also credit blackholes as helpful in learning how galaxies began to form. Paragraph 2_____________A:What Happens to the Objects Around a Black Hole?B:Is There Proof That Black Holes Really Exist? C:How Were Black Holes Named? D:What Are Different Types of Black Holes?E:What Are Black Holes Made of?F:How Are Black Holes Formed?
