153. b等于什么时，直线y=x²+bx+4与x轴无交点 1）-2 2）0 3）6 V2 y=x^2+n*x+4，在n取哪个值得时候，Y跟x轴没交点 I 0 II 2 III 6 答案：选I和II的 154. (5x²-35x-150)/(3x²-9x-30)=0注意!!!!!!!!!题目问的是the sum of 解，所以是7
语法：估计我的语法很差，基本都是单复数什么的，没什么可说的，能记得的： 1、each 的独立主格 each 。。。 +动词+ed 2、同位语 3、3times greater than.../3 times as great as
作文： ai：fuel resources are limit,所以international agreement 应该adopted to reduce。。。。。。 aa：人力资源部门负责公司profits 下降那个，自己找吧，赫赫
lost city ,英文有用的那几段：
One such revelation occurred in December 2000.An expedition mapping a submerged mountain known as the Atlantis Massif, midwaybetween Bermuda and the Canary Islands and half a mile under the surface of theNorth Atlantic, came across a pillar of white rock as tall as a 20-storybuilding rising from the sea¬floor. Using the remotely operated ArgoII vehicleand the manned submersible Alvin, scientists surveyed and sampled themysterious formation. Although time constraints limited their investigation toa single Alvin dive, the researchers were able to collect enough information todetermine that the white pillar was just one of several such structures in thearea that were emitting heated seawater. They had discovered a field of undersea hot springs theynamed the Lost City Hydrothermal Field. It was unlike anything seen before, includingthe now famous black smokers. Strange Chemistry Scientists have known about underseahydrothermal ventssince the 1970s. The black smoker systems are the most familiar; they occur atmid-ocean ridges—those strings of volcanoes overlying spots where tectonicplates are pulling away from one another. The water at these vents can reachtemperatures above 400 degrees Celsius because of their proximity to moltenrock. With a pH similar to lemon juice, the scorching water leaches sulfide,iron, copper and zinc as it filters through the volcanic rocks below theseafloor. As this hot,acidic fluid then rises back to the surface of the seafloor, it is discharged through the ventsintocold seawater,where the dissolved metal sulfides quickly cool and precipitate out of thefluid, producing a cloudy mix that looks like billowing black smoke. These metal sulfidesaccumulate into ever taller chimneys atop the vents. Despite their hostilechemistry, the areas surrounding these vents teem with exotic animals, such as giant, red-tippedRiftia tube worms, which lack both mouths and guts but thrive by a symbioticassociation with internal bacteria that consume poisonous hydrogen sulfide gasemanating from the vents. Compared with the savage black smokerenvironment, the Lost City vents are eerily tranquil.安静 Locatedabout 15 kilometers to the west of the tectonic plate boundary at theMid-Atlantic Ridge, this vent field atop the Atlantis Massif is too distant forrising magma to heat the fluids to the blistering temperatures found at blacksmokers. Instead the water is heated by circulation through the merely warmrock below, and the highest measured temperature is only 90 degrees C. Neither arethe Lost City fluids acidic. They are alkaline, with a pH between 9 and 11—similar to milk ofmagnesia or household ammonia solution. Because these waters cannot readilydissolve high concentrations of metals such as iron and zinc, Lost City does not produce themetal sulfideplumes that characterize black smokers. Rather Lost City vent waters are richin calcium, which on mixing with seawater produces calcium carbonate (limestone). Thislimestone forms giant whitechimneys, the largest of which towers nearly 60 meters above thesea¬floor—significantlytaller than the loftiest black smoker chimney. Hydrogen is full of energy as a consequence of its ability to transfer electrons to othercompounds, such as oxygen, releasing energy in the process. Compoundsthat can readily donate electrons to other compounds are described somewhatconfusingly as “chemically reduced.” Scientists have long suspected that reduced gases played animportant role in the origin of life on Earth. In the 1920s Russian biochemistAlexander Oparin and British evolutionary biologist J.B.S. Haldane eachsuggested that the primitive atmosphere of Earth might have been very rich inreduced gases such as methane, ammonia and hydrogen. If the atmosphere had highconcentrations of these gases, they proposed, the chemical ingredients required for life might haveformed spontaneously. Lost City is a natural laboratory for testingthese ideas. In 2008 chemist Giora Proskurow¬ski of the Woods HoleOceanographic Institution and his colleagues published a paper in the journalScience demonstrating that the hydrothermal fluids at Lost City do indeedcontain small organic compounds such as methane, ethane and propane. Other worksuggests that the reactions at Lost City also produce small organic acids suchas formate and acetate. Together these findings confirm that the reducedconditions at the Lost City vents could support the types of chemical reactionsnecessary to create organic compounds from inorganic compounds—a simple butcritical step in prebiotic chemistry. The findings from Lost City also bolsterhypotheses about where else in our solar system life might exist or haveexisted in the past. Any planet or moon containing both peridotite and liquid water—theingredients necessary for serpentinization—could conceivablysupport life-forms analogous to microbes at Lost City. Evidence ofthese components is strongest on Mars and on Jupiter’s moon Europa. Indeed,researchers have already detected methane in the modern Martian atmosphere.Whether it comes from microbes or chemical reactions in the planet’s rocks—orboth—remains uncertain, however
作者: 梦离ouzi 时间: 2012-2-21 08:15
恭喜楼主···你老公肯定开心。作者: miss绿光 时间: 2012-2-21 09:00
有个英文顶呱呱的老公真好! 有个有好JJ分享给大家的CDer真好！ 谢谢你的lost city啦! ヾ(＠⌒ー⌒＠)ノ作者: yuyyyan 时间: 2012-2-21 10:08
lost city tai geili la !!!! thanks~~~作者: zgloria 时间: 2012-2-21 10:17
你太厉害了，我扎扎实实复习了三个月，结果才考了590。准备下个月再考，可是现在患有严重的看Gmat障碍症，根本看不进去书，纠结死了。。。。。作者: aivar 时间: 2012-2-21 10:41
更新了一些自己能记得住的jj，希望能有所帮助。
*S^2