已知{an}为等差数列,其公差为-2,且a7是a3与a9的等比中项,Sn为{an

题型:选择题

问题:

已知{an}为等差数列,其公差为-2,且a7是a3与a9的等比中项,Sn为{an}的前n项和,n∈N*,则S10的值为

A.-110
B.-90
C.90
D.110
考点:等比中项等差数列的前n项和
题型:选择题

读图,回答下列各项

(1)将七大洲的名称填在图上适当的位置上.

(2)将四大洋的名称填在图上适当的位置上.

(3)南美洲与北美洲的分界线是______ 运河,亚洲与北美洲的分界线是______ 海峡

(4)非洲位于亚洲的______方向,大洋洲在印度洋的______岸.

(5)赤道穿过的大洋有______洋、______洋和______洋.

(6)太平洋被______个大洲包围,位于太平洋东岸的是______洲和______洲.

题型:选择题

莱姆病早期皮肤损害时常选用的药物是()

A.红霉素

B.阿莫西林

C.青霉素

D.头孢曲松

E.阿奇霉素

题型:选择题

下列括号中的分离方法运用得当的是

[ ]

A.植物油和自来水(蒸馏)

B.水溶液中的食盐和碘(分液)

C.SiO2和CaCl2(溶解、过滤、蒸发)

D.自来水中的杂质(萃取)

题型:选择题

无符号二进制整数1001111转换成十进制数是( )。

A.79

B.89

C.91

D.93

题型:选择题

Part of the debate about culture revolves around issues of perspective and ownership. Within a nation such (1) the United States—a nation whose cultural heritage includes elements from every corner of the world (2) are a great many perspectives coexisting and intertwining in the cultural fabriC.When we all ask (3) as individuals, "what belongs to me, to my culture " we are rewarded with a spectacular variety of (4) ; in this way, different perspectives and ownership of different cultural traditions enriches everyone. But when we ask " (5) belongs to us, to our culture " we ask a much harder question. Do the people of the (6) States, or of any culturally complex human society, necessarily share common cultural elements If so, who gets (7) decide what those elements are
This debate is a crucial one in many cultures throughout the world (8) . In the US, the debate promises to impact the way we educate our children—that is, (9) manner and shape in which culture reproduces itself—and the way we write our laws. In (10) countries, equally crucial issues are at stake.
For many people, what is at stake is the character (11) US national identity. Hirsch argues that this identity needs to become less culturally fragmented; others, like Walker, (12) that the national character gets its strength from cultural diversity, from the freedom (at home and in (13) ) to celebrate, honor, and reproduce different cultural traditions. Those who take this latter view follow the reasoning (14) Shweder, arguing that we need to accept that there are multiple valid cultural perspectives and that two (15) perspectives can both be valid even though they might contradict one another.
Recognize that the position you (16) in this debate about culture—whatever position you take—is a political one with implications (17) what we should value, what we should praise, what we should accept, what we should teach. When (18) reflect on this debate, when you contribute your own voice to the discussion, try to be (19) of the implications that follow from your position. When you listen to the voices of others, try to (20) with awareness, deciding for yourself what is at stake and how their positions relate to your own.

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