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1、摩尔斯电码对表：
http:防//www. 吞qsl.net/bg3删tt/zl/me除sdm.htm

2、宇宙背景辐射
如何通俗的解释为什么微波背景辐射表明，宇宙还是比较平的？https:防//ww吞w.zhihu.c删om/questi除on/29141448
宇宙背景辐射告诉了我们什么？http:/防/m.baidu.com/from吞=844b/bd_page_type=1/ss删id=0/uid=0/pu=usm%400%2Csz%401321_1001%2Cta%40utouch_2_除4.3_3_/baiduid=2D15AE234B5BC8BB0305B422A102A5D6/w=0_10_%E5%AE%87%E5%AE%99%E8%83%8C%E6%99%AF%E8%BE%90%E5%B0%84/t=wap/l=3/tc?ref=www_utouch&lid=9193236396241736566&order=2&vit=osres&tj=www_normal_2_0_10_title&m=8&srd=1&dict=32&title=%E5%AE%87%E5%AE%99%E8%83%8C%E6%99%AF%E8%BE%90%E5%B0%84%E5%91%8A%E8%AF%89%E4%BA%86%E6%88%91%E4%BB%AC%E4%BB%80%E4%B9%88%3F_%E5%A4%A7%E7%A7%91%E6%8A%80%E6%9D%82%E5%BF%97%E7%A4%BE%E6%89%93%E9%80%A0%E6%9C%80...&sec=10499&di=6a5543603d60c126&bdenc=1&nsrc=IlPT2AEptyoA_yixCFOxXnANedT62v3IEQGG_ypP_Gfn6Jbte4viZQRAY8KhVnCTC6DwrmaHf1YYwk0iKixuldU4f4IndjQq7Ufbd48xdhPsHRwPhxZmDQCSH7wk-OHy