姜片虫病引起发病的原因有（） A.主要为机械性损伤 B.虫体代谢产物引起的毒性反应

根据短文内容，完成下面的句子，每空一词。（每小题2分，共10分）

Do you like drinking Coke? As a symbol of American culture, Coca-Cola is liked by many people, especially young people around the world．But from now on, perhaps it will be difficult for students in the US to get it in school. A new agreement (协议) will stop almost all sales of high-sugar fizzy (起泡的) drinks in American schools.

The agreement allows only juice, milk and water to be sold in primary schools and middle schools. It will help 35 million young people choose healthy drinks.

Childhood obesity (肥胖) has become a big problem in America. A report shows that obesity has risen so fast in teenagers in the past 25 years. The main reason is that kids eat too much junk food and drink too much Coke.

The UK has already used similar ways to fight obesity. A recent study shows that people in the UK are much healthier than those in the US. However, it's better late than never. Now American schools are trying to lead students to healthier lives.

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小题1:Coca-Cola is __________ by many __________ people around the world.

小题2:From now on, perhaps it won’t be __________ for students in the US to __________ Coke in school.

小题3: According to the agreement, only juice, milk and _______ are allowed to be sold in American _______.

小题4:A report __________ that teenager obesity has risen so __________ in the past 25 years.

小题5:People in the __________ are much __________ than those in the US.

（）的目的是保证汽车沿路面直线行驶。

晏阳初针对四大问题的四大教育，最为根本的是( )

A．文艺教育

B．生计教育

C．卫生教育

D．公民教育

超声仪的组织定征技术的作用是（）。

A.可对细胞学进行分析

B.分析组织结构的声学特性的改变

C.无任何价值

D.虽影响因素较多，但结果非常准确

E.可代替心导管检查方法

请简述网络优化的目的与一般流程。