19．
Teeth are important parts of our body．If we want to keep our teeth healthy and clean，we should brush teeth at least twice a day．How can we brush our teeth？Of course by using toothpaste and toothbrushes．But do you know the history of toothpaste？
About 7，000years ago，Egyptians（埃及人）were the first to start using toothpaste．Do you know what they used to wash their teeth？You may feel very surprised!They washed their teeth with tortoise（海龟）blood three times a year．
Later，Greeks（希腊人）began to brush teeth，too，They used stones as toothpaste．Even kids at that time put stones into their mouths to clean their teeth．That sounds funny．When they used stones to clean their teeth，they should be careful not to injure their teeth．
Modern toothpaste started in the 1800s．At that time，there was a dentist and his name was Dr．Peabody，he was the first person to make toothpaste．The toothpaste he made was a little similar to the one we use today．
46．Cwere the first to start using toothpaste．
A．Chinese B．Americans C．Egyptians
47．Greeks usedBto brush teeth．
A．blood B．stones C．sweets
48．The underlined word"injure"probably means"B"in Chinese．
A．保护 B 损伤 C 清洗
49．After reading the passage，we can knowA．
A．how often we should brush teeth
B．how long we should brush teeth at a time
C．when Chinese began to use toothpaste
50．What's the best title for the passage？C
A．A Great Dentist B．Important to Teeth C．History of Toothpaste．
