英语课上的问题 帮我答出来我给30分!

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  • 1.Toothpaste was used as long ago as 500 BC in both China and India; however,modern toothpastes were developed in the 1800s.In 1824,a dentist named Peabody was the first person to add soap to toothpaste.John Harris first added chalk as an ingredient to toothpaste in the 1850s.In 1873,Colgate mass-produced the first toothpaste in a jar.In 1892,Dr.Washington Sheffield of Connecticut manufactured toothpaste into a collapsible tube.Sheffield's toothpaste was called Dr.Sheffield's Creme Dentifrice.In 1896,Colgate Dental Cream was packaged in collapsible tubes imitating Sheffield.Advancements in synthetic detergents made after WW II allowed for the replacement of the soap used in toothpaste with emulsifying agents such as Sodium Lauryl Sulphate and Sodium Ricinoleate.A few years later,Colgate started to add fluoride to toothpaste.

    2.32 for the adult

    3.bacteria readily metabolize various amino acids from foods,salivary peptides and proteins in oral cavity,and release gases as by-products -- a process called bacterial putrefaction.

    4.Black tea is good for teeth