没看够最近青岛崂山的回旋镖荚状云，可以来欣赏一下昨天俄罗斯堪察加的叠层蛋糕荚状云。
2021年5月19日俄罗斯堪察加边疆区彼得罗巴甫洛夫斯克附近科里亚克火山和阿瓦钦斯基火山上空的荚状云。
：antonuzloff；kam_peninsula（2～3）；g.o.l.d.b.e.r.t；kovaleva.mar；l_jjclydoydktdktdktsktdmgd（6～9）

【What Empowers Ethnic Minority Parents to Change towards Supporting Their Children's Learning of Chinese in a Hong Kong Home-School-Community Project?】

Based on an analysis of the critical incidents associated with the changes in a Hong Kong Home-School-Community Project, two critical aspects are identified in the parental empowerment process, which include: 1) Parents' seeing their children making improvements in their Chinese learning; 2) Parents' seeing themselves being able to play a part in the activities related to the learning and expanding their own community social networks. (Authored by Shek-Kam Tse, et al., from The University of Hong Kong, China.)

DOI: 10.4236/jss.2021.95012 https://t.cn/A6VbJTaQ

阿基米德正七边形尺规作图法

世界千古难题，
终有一法；
阿基米德，
正七边形尺规作图法！！！

作法如下：
❶作⊙O₁，且作⊙O₁的内接正△AMN。
❷以M为⊙心1/2AM长为半径画弧交⊙O₁干K。
❸连接AK，且作∠KAM的角平分线AO₂交NO₁的延长线于O₂。
❹以O₂为⊙心O₂A为半经作⊙O₂。
❺连接AK，且延长AK交⊙O₂于P。
❻连接PM，则PM就是⊙O₂的内接正七边形的边长。

[心][心][心][心][心][心][心]如图片。在⊙O₂中，七边形ABCPMDE就是⊙O₂的⊙内接正七边形。#我是表情帝##宝宝的少女心#

(待续。证明！！！阿基米德正七边形尺规作图法的证明繁琐但神奇美妙)！！！事实上，阿基米德正七边形尺规作图法的证明，添加的辅助线比作图法更多。 https://t.cn/Rxr08Lm