2019.1.31 english index start
2019.2.6 " cancel "or"get rid of"are changed to eliminate
2019.5.20 add title 4
2019.12.25 modify the name of title 3
2020.1.1 start title 3 main text
2020.4.3 tart title 3-2
2022.3.8 add title3-3 revealing the falsity about penicillin
2023.1.20 corrected a few phrase
2023.4.9 change the name of title 2