课时作业14
ⅰ.阅读理解
a
(2013•安徽卷)the healthy habits survey(调查)shows that only about one third of american seniors have correct habits.here are some findings and expert advice.
1．how many times did you brush your teeth yesterday?
●finding：a full 33% of seniors brush their teeth only once a day.
●step：remove the 300 types of bacteria in yo
