若θ是任意实数,则方程x2+4y2sinθ=1所表示的曲线一定不是( ) A.圆

题型:选择题

问题:

若θ是任意实数,则方程x2+4y2sinθ=1所表示的曲线一定不是(  )

A.圆

B.双曲线

C.直线

D.抛物线

考点:圆锥曲线综合
题型:选择题

根据汉语提示,将单词的适当形式写在答题卡相应在的横线上。

小题1:These details are easily          (忽略), so you should pay attention to them.

小题2:The industry     (繁荣)attracted Europeans including Jewish people.

小题3:Your return ticket is         (有效的)for three months.

小题4:Thank you for your help.        (否则), we would not have finished our task on time.

小题5:This hotel is so popular that guests are asked to make      (预定)in advance.

题型:选择题

两个实心的金属球体积相等,质量不等,则 [ ]

A.它们的密度不相等,质量大的金属密度大

B.它们的密度不相等,质量小的金属密度大

C.它们的密度相等

D.条件不够,无法判断

题型:选择题

根据下列所给情景回答有关问题:

(1)《三国演义》中有这样一个故事:诸葛亮率领的汉军误饮了“哑泉”.哑泉,“人若饮之,则不能言,不过旬日必死”.后来,汉军将士经地方隐士指点,饮了万安溪的“安乐泉”水方才转危为安.“哑泉”中含有的物质可能是______;“安乐泉”中所含的化学物质可能是______.(填字母序号)

A.NaCl   B.CuSO4   C.Na2SO4  D.Ca(OH)2  E.CaCl2  F.NaNO3

(2)寻找规律,在横线上填上相应的化学式或名称:

有机化合物里有一类物质叫烷烃,分子中碳、氢原子个数呈一定的规律.CH4(甲烷)、C2H6(乙烷)、C3H8(丙烷)、

C4H10(______)、______(戊烷)…

(3)工业上采用电解饱和食盐水制备氢氧化钠:2NaCl+2H2O

 电解 
.
 
2NaOH+Cl2↑+H2↑.因饱和食盐水中混有一定量的NH4Cl,在电解时会引起爆炸.为除去NH4Cl,工业上常利用电解后的碱性废液、Cl2与NH4Cl反应(其中Cl2与NH4Cl化学计量数分别为3、2),使NH4Cl转化成N2.请说出此方法的两个优点:①______,②______.

题型:选择题

数据库管理系统的体系结构是______。

A.两级模式结构和一级映像
B.三级模式结构和一级映像
C.三级模式结构和两级映像
D.三级模式结构和三级映像

题型:选择题

A study released a little over a week ago, which found that eldest children end up, on average, with slightly higher IQ’s than younger siblings, was a reminder that the fight for self- definition starts much earlier than freshman year. Families, whatever the relative intelligence of their members, often treat the firstborn as if he or she were the most academic, and the younger siblings fill in other niches: the wild one, the flirt.

These imposed caricatures, in combination with the other labels that accumulate from the sandbox through adolescence, can seem over time like a miserable entourage of identities that can be silenced only with hours of therapy. But there’s another way to see these alternate identities: as challenges that can sharpen psychological skills. In a country where reinvention is considered a birthright, many people seem to treat old identities the way Houdini treated padlocked boxes: something to wriggle free from, before being dragged down. And psychological research suggests that this ability can be a sign of mental resilience, of taking control of your own story rather than being trapped by it.

The late-night bull sessions in college or at backyard barbecues are at some level like out-of-body experiences, allowing a re-coloring of past experience to connect with new acquaintances. A more obvious outlet to expand identity--and one that’s available to those who have not or cannot escape the family and community where they’re known and labeled-- is the Internet. Admittedly, a lot of the role-playing on the Internet can have a deviant quality. But researchers have found that many people who play life-simulation games, for example, set up the kind of families they would like to have had, even script alternate versions of their own role in the family or in a peer group.

Decades ago the psychologist Erik Erickson conceived of middle age as a stage of life defined by a tension between stagnation and generativity-a healthy sense of guiding and nourishing the next generation, of helping the community. Ina series of studies, the Northwestern psychologist Dan P. McAdams has found that adults in their 40s and 50s whose lives show this generous quality - who often volunteer, who have a sense of accomplishment - tell very similar stories about how they came to be who they are. Whether they grew up in rural poverty or with views of Central Park, they told their life stories as series of redemptive lessons. When they failed a grade, they found a wonderful tutor, and later made the honor roll; when fired from a good job, they were forced to start their own business.

This similarity in narrative constructions most likely reflects some agency, a willful reshaping and re-imagining of the past that informs the present. These are people who, whether pegged as nerds or rebels or plodders, have taken control of the stories that form their identities.

In conversation, people are often willing to hand out thumbnail descriptions of themselves: "I’m kind of a hermit. " Or a talker, a practical joker, a striver, a snob, a morning person. But they are more likely to wince when someone else describes them so authoritatively.

Maybe that’s because they have come too far, shaken off enough old labels already. Like escape artists with a lifetime’s experience slipping through chains, they don’t want or need any additional work. Because while most people can leave their family niches, schoolyard nicknames and high school reputations behind, they don’t ever entirely forget them.

Psychologists seem to believe that if adults want to remake their identity, they need to()

A. tell their psychologists very similar stories about themselves

B. command the identity-forming factors themselves

C. quit their jobs and start their own business

D. hire a wonderful tutor to get themselves into the honor roll

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