以洛阳为中心，北达涿郡，南至余杭的古代工程是（    ）

在中国传统文化中，为官之德被视作治国理政的主导因素，相关的经典论述内容丰富、数量繁多。下列选项中，古今表述内涵一致的是（    ）

①“不受虚言，不听浮术，不睬华名、不兴伪事”——求真务实，力戒形式主义

②“当官避事平生耻，视死如归社稷心”——廉洁自律，坚持尚俭戒奢

③“不作无补之功，不为无益之事”——科学决策，提高行政效率

④“去民之患，如除腹心之疾”——处事公正，依法规范行政

    What is the strongest part of your body? Your head? Bones? It's your teeth! There is a special thing called enamel (牙釉质) in teeth. It is the hardest thing in the human body and keeps bacteria (细菌) away. However, teeth are vulnerable (易受伤害的) to problems and disease. September 20 is National Teeth-loving Day in China. Let's pay attention to the health of our teeth.
    Tooth     (1)   are    (1)   around the world. Most children and young adults have tooth decay (龋齿). A study published on China Health Monthly magazine this year showed that 40.74 percent of a sample (抽样) of 1,306 Chinese students under age 15 had decayed teeth.
(2)Food that is rich in sugar increases the risk of tooth decay. After you eat, bacteria go crazy over the sugar on your teeth, like ants at a picnic. The bacteria turn sugar into acids (酸) that eat away at tooth enamel.This cause holes in your teeth.
    Another common problem is crooked teeth (龅牙). When your new teeth begin to grow and the old teeth haven't fallen out, there isn't enough space for the new ones. This causes crooked teeth.
    Don't worry. Here are some ways to keep your teeth healthy.
    Brush at least twice a day – in the morning and before bedtime.
    Learn to use dental floss (牙线). The floss gets rid of food that's hidden where your toothbrush can't get it.
    Visit a dentist. He or she can check if you have any dental problems and help you clean your teeth.
    Pay attention to what you eat. It is better to eat lots of fruits and vegetables instead of fries and drink water instead of soda.
    Wear braces (牙套) to make your teeth straight and beautiful.