农民在选种时,都选用粒大而饱满的种子,原因是( ) A.这样的种子有较强的抗病力

题型:选择题

问题:

农民在选种时,都选用粒大而饱满的种子,原因是(  )

A.这样的种子有较强的抗病力

B.这样的种子发芽率强

C.这样的种子发育完全且贮藏有丰富的营养物质

D.这样的种子有生命力

考点:种子萌发的条件和过程
题型:选择题

乙型肝炎的主要传播途径是()

A.消化道传播

B.血液、血制品传播

C.呼吸道传播

D.直接接触

E.蚊虫叮咬

题型:选择题

创造市场将竞争机制引入公共物品和服务的提供,但是存在不公平的市场化政策工具是()。

A.民营化

B.权力下放

C.放松管制

D.产权交易

题型:选择题

Most critical plot points in Harry Potter and the Sorcerer’s Stone came from J. K. Rowling’s imagination, but Flamel and his powerful pebble were legendary long before Harry went to Hogwarts. The 14th century alchemist created the philosoper’s stone (called "sorcerer’s" in U.S.editions of Potter ), with which he turned mercury to gold and gained eternal life. But Flamel’s tale—like his stone and his science—was no more real than a magic.

The philosopher’s stone was the key to alchemy, the medieval predecessor to chemistry that aimed to cure all illnesses, make the elixir of life, and transmute base metals into gold. The last made perfect sense at the time. The Aristotelian theory of elements stated that all things consisted of fire, air, water, and earth. So a little shift in one metal’s composition could create gold.

Flamel was renowned as an alchemical success. In 1382, after 25 years of studying an ancient book by "Abraham the Jew", he is said to have produced the philosopher’s stone. His texts, notably a deconstruction of the "Abraham" work, were standard reading for aspiring scientists like Isaac Newton.

Many alchemists believed Flamel faked his 1418 death and that of his wife. Rumored sightings in the 18th century placed them at the Paris Opera. As late as 1816 there were reports of people searching Flamel’s former house for secrets of the stone.

Contemporary historians say, a Nicolas Flamel did live in Paris in the 1300s and endowed many churches and hospitals with his wealth. But he was no alchemist. "He got his money in pedestrian ways—his wife’s earlier marriages, real-estate speculation," says lawrence Principe, author of The Aspiring Adept. Anachronisms, style of language, and the lack of earlier copies indicate that none of "his" writings originated prior to the 1500s.

"This sort of thing happens in alchemy," says Bill Newman, author of alchemical history Gehennical Fire. When an alchemist couldn’t back up his ideas, he might publish them in the guise of a "lost" work. Flamel’s wealth made a good candidate for alchemical identity theft.

Flamel writings and sightings faded with alchemy’s prestige. And the closest anyone’s come to the philosopher’s stone is Rowling. In her hands, it has yielded not just gold but eternal (shelf) life as well.

It can be inferred that Flamel was believed ().

A. to have spend 25 years with "Abraham the Jew"

B. to be the creator of the philosopher’s stone

C. to be the founder of alchemy

D. to have cast light on Newtonian mechanics

题型:选择题

阅读下列材料,结合所学知识回答问题。

材料一

郡城之东,皆习机业;织文曰缎,方空曰纱。工匠各有专能,匠有常主,计日受值。有他故,则唤无主之匠代之,曰“换代”。无主者,黎明立桥头以待……若机房工作减,此辈衣食无所矣。

——《苏州风俗考》

材料二

1757年,清朝乾隆皇帝诏告天下,划定广州十三行为全国唯一对外贸易口岸,史称“一口通商”。

材料三

1913~1922年中国进出口面粉值变化表(单位:海关两)

材料一反映的社会现象的实质是什么?

题型:选择题

下肢静脉曲张能否手术的关键是

A.曲张静脉病变程度
B.交通静脉瓣膜功能是否健全
C.深静脉是否通畅
D.小隐静脉是否受累
E.以上均不是

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