①适当提高二氧化碳浓度  ②提高氧气浓度 

③适当延长光照时间  ④形成高温环境  ⑤人工形成昼夜温差较大的条件．

    Birthdays often involve surprises.But this year's surprise on the birthday of the great British playwright William Shakespeare is surely one of the most dramatic.

    On April 22,one day before his 441st birthday anniversary,experts discovered that one of the most recognizable portraits（画像）of William Shakespeare is a fake.This means that we no longer have a good idea of what Shakespeare looked like."It's very possible that many pictures of Shakespeare might be unreliable because many of them are copies of this one,"said an expert from Britain's National Portrait Gallery.

    The discovery comes after four months of testing using modern chemistry technology.The experts from the gallery say the image—commonly known as the "Flower portrait"—was actually painted in the 1800s,about two centuries after Shakespeare's death.The art experts who work at the gallery say they also used modern chemistry technology to check the paint on the picture.These checks found traces of paint dating from about 1814.Shakespeare died in 1616,and the date that appears on the portrait is 1609.

    “We now think the portrait dates back to around 1818 to 1840.This was when there was a renewed interest in Shakespeare's plays,”Tarnya Cooper,the gallery's curator（馆长）,told the Associated President.

    The fake picture has often been used as a cover for collections of his plays.It is called the Flower portrait because one of its owners,Desmond Flower,gave it to the Royal Shakespeare Company.

    “There have always been questions about the painting,”said David Howells,curator for the Royal Shakespeare Company.“Now we know the truth,we can put the image in its proper place in the history of Shakespearean portraiture.”

    Two other images of Shakespeare,are also being studied as part of the investigation and the results will come out later this month.

    陈涉世家陈胜者，阳城人也，字涉。吴广者，阳夏人也，字叔。陈涉少时，尝与人佣耕，辍耕之垄上，怅恨久之，曰：“苟富贵，无相忘。”佣者笑而应曰：“若为佣耕，何富贵也？”陈涉太息曰：“嗟乎，燕雀安知鸿鹄之志哉！”

    二世元年七月，发闾左谪戍渔阳，九百人屯大泽乡。陈胜、吴广皆次当行，为屯长。会天大雨，道不通，度已失期。失期，法皆斩。陈胜、吴广乃谋曰：“今亡亦死，举大计亦死，等死，死国可乎？”陈胜曰：“天下苦秦久矣。吾闻二世少子也，不当立，当立者乃公子扶苏。扶苏以数谏故，上使外将兵。今或闻无罪，二世杀之。百姓多闻其贤，未知其死也。项燕为楚将，数有功，爱士卒，楚人怜之。或以为死，或以为亡。今诚以吾众诈自称公子扶苏、项燕，为天下唱，宜多应者。”吴广以为然。乃行卜。卜者知其指意，曰：“足下事皆成，有功。然足下卜之鬼乎！”陈胜、吴广喜，念鬼，曰：“此教我先威众耳。”乃丹书帛曰“陈胜王”，置人所罾鱼腹中。卒买鱼烹食，得鱼腹中书，固以怪之矣。又间令吴广之次所旁丛祠中，夜篝火，狐鸣呼曰“大楚兴，陈胜王”。卒皆夜惊恐。旦日，卒中往往语，皆指目陈胜。

    吴广素爱人，士卒多为用者。将尉醉，广故数言欲亡，忿恚尉，令辱之，以激怒其众。尉果笞广。尉剑挺，广起，夺而杀尉。陈胜佐之，并杀两尉。召令徒属曰：“公等遇雨，皆已失期，失期当斩。借第令毋斩，而戍死者固十六七。且壮士不死即已，死即举大名耳，王侯将相宁有种乎！”徒属皆曰：“敬受命。”乃诈称公子扶苏、项燕，从民欲也。袒右，称大楚。为坛而盟，祭以尉首。陈胜自立为将军，吴广为都尉。攻大泽乡，收而攻蕲。蕲下，乃令符离人葛婴将兵徇蕲以东。铚、酂、苦、柘、谯皆下之。行收兵。比至陈，车六七百乘，骑千余，卒数万人。攻陈，陈守令皆不在，独守丞与战谯门中。弗胜，守丞死，乃入据陈。数日，号令召三老、豪杰与皆来会计事。三老、豪杰皆曰：“将军身被坚执锐，伐无道，诛暴秦，复立楚国之社稷，功宜为王。”陈涉乃立为王，号为张楚。当此时，诸郡县苦秦吏者，皆刑其长吏，杀之以应陈涉。