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问题 选择题

图1为一列简谐横波在t=0时的波形图，P是平衡位置在x=1cm处的质元，Q是平衡位置在x=4cm处的质元。图2为质元Q的振动图像。则

A．t=0.3s时，质元Q的加速度达到正向最大

B．波的传播速度为20m/s

C．波的传播方向沿x轴负方向

D．t=0.7s时，质元P的运动方向沿y轴负方向

答案

答案：C

题目分析：由图2可知，t=0.3s时，质元Q的位置在正向最大位移处，故其加速度是达到反向最大，故A是不对的；由图1可知，波长为8cm，由图2可知，周期为0.4s，故波速为v==20cm/s，所以B也是不对的；由于质元Q在t=0时的振动方向是向下的，故可以判断出波的传播方向是沿x轴的负方向传播的，故C是正确的；当t=0.7s时，实际上是经过1T，0位置处的质元会运动到负的最大位移处，所以P点的质元会运动到x轴以下正在沿y轴的正方向运动的位置，故D是不对的。

选择题

4. The huge picture looks more beautiful _____ the blue sky.

A．against

B．to

C．over

D．Under
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填空题

B The Culture Debate in the US:Whose Culture Is This ,Anyway 美国的文化辩论：空间是谁的文化？
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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