[todo list]sed & awk GNU manual
editorials:
https://www.ft.com/ft-view
非常重要的英文语法:
https://grammartips.homestead.com/possessivewithgerund.html
sed & awk GNU manual
https://www.gnu.org/software/sed/manual/
https://www.gnu.org/software/gawk/manual/
https://www.math.utah.edu/docs/info/gawk_toc.html
popular science-related
https://spaceplace.nasa.gov/laser/en/
algorithm:
https://www.programiz.com/dsa/stack
algebraic geometry
number theory
看懂费马大猜想
https://ncts.ntu.edu.tw/scientificprograms_detail.php?gid=1&k=0
https://www.math.purdue.edu/~arapura/graph/conic.html