图中的实线表示t 时刻的一列简谐横波的图像,虚线则表示(t+△t)时刻该波的图像

题型:选择题

问题:

图中的实线表示t 时刻的一列简谐横波的图像,虚线则表示(t+△t)时刻该波的图像.设T为该波的周期.则△t的取值  .(其中n=0,1,2,3…)

A.若波沿x轴正方向传播,△t=(n+1/4)T

B.若波沿x轴负方向传播,△t=(n+1/4)T

C.若波沿x轴正方向传播,△t=(n+3/4)T

D.若波沿x轴负方向传播,△t=(n+3/4)T

考点:波的图像
题型:选择题
I have a good friend and we are like sisters. But sometimes the things she does make me     I’m independent and I don’t depend on others. I like to be different      others. But she does everything the same      I do. For example, I have friends from        groups, because I want different friends. But she      them and tries to make friends with them. Also, I got a nice hat and she got the same one. I want to color my hair and she wants to color      ,too.  There are more things      that. I like her very much because she is a great friend, but I can’t      the things she does sometimes. I don’t want to say     to her because it ‘ll make things worse I don’t know      to do. Can you give me some advice?
小题1:
A.excitedB. tiredC.angryD. cool
小题2:
A.withB. asC.fromD.with
小题3:
A.IfB. asC.soD.and
小题4:
A.necessaryB.different C.importantD.famous
小题5:
A.meetsB.watchesC.beatsD.forgets
小题6:
A.sheB.herC.she’sD.hers
小题7:
A.ofB.forC.aboutD.like
小题8:
A.finishB.aboutC.affordD.stand
小题9:
A.nothingB.anythingC.somethingD.everything
小题10:
A.whomB.whenC.whereD.what
题型:选择题

女,63岁,突然出现剧烈头痛6小时,伴呕吐无发热,无高血压病史,右侧瞳孔对光反射消失,上眼睑下垂,眼球向上、下及内侧运动受限,颈项强直,克氏征阳性。CT示右大脑外侧裂,枕大池呈高密度影。

为进一步治疗及预防,最有意义的检查是()

A.脑电图

B.颅脑X线平片

C.腰穿

D.头颅增强CT扫描

E.全脑血管造影

题型:选择题

煤矿倾斜井巷中升降物料的绞车,其滚筒上缠绕的钢丝绳层数严禁超过________?

题型:选择题

马氏漏斗粘度计的单位是S。

题型:选择题

承包商可以向业主提出索赔的情形包括()

A.监理工程师提出的设计变更导致费用的增加

B.承包商为了保证工程质量而增加的措施费

C.分包商返工造成费用增加,工期拖延

D.承包商自行采购材料的质量有问题导致的费用增加,工期拖延

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