简述马克思主义体育观产生的背景、简要内容来源和意义。

体虚易感冒者平素宜服（）

A.四物汤

B.玉屏风散

C.八珍汤

D.六味地黄丸

E.肾气丸

会计的基本职能是（）。

A.预测和决策

B.核算与监督

C.检查和评价

D.分析和考核

市场上已有的但本企业以前从未生产过的产品也属于新产品。

Have you ever thought, “I wish I could take a year off and just travel around the world”?

Well,three lucky American teenagers were able to do just that．The teens—two males and one female--got an all-expenses paid, yearlong hike to five continents.

This trip didn’t include any five-star hotels or shopping funs．Eighteen-year-old Jamie Fiel from Keller, Texas, 17-year-old Arsen Ewing from Canyon, California, and 16-year-old Tyler Robinson from Lincoln, Massachusetts, didn’t expect fancy treatment．They signed up for the experience of a lifetime, which included hard work, often uncomfortable accommodations, and encounters with（遭遇） some of nature’s most dangerous animals and environments.

Jamie, Arsen, and Tyler were among hundreds of high school kids nominated by their science teachers to take this trip．Earthwatch Institute sponsored this adventure．Each year, Earthwatch employs thousands of volunteers worldwide to help with scientific research projects．

The group went all around the world to get a close look at the most pressing environmental issues of our time．Their assignments were as varied as their locations, and included measuring and attending pink flamingos in Kenya’s Great Rift Valley, and tracking giant sea turtles in Costa Rica.

As they worked with the Earthwatch scientists, Jamie, Arsen, and Tyler began to understand that we are at a critical moment in the life of our planet．Time for change is running out．As the teens went from country to country and witnessed different environmental dangers and challenges, they understood that solutions to important environmental issues start with the power of one person's actions．They realized that each of them can make a difference.

小题1:These teenagers went on the journey around the world _____.

A．to experience the most serous environmental problems on the earth

B．to bring the kindness of America to the other parts of the world

C．to go on sightseeing around the world

D．to call on more teenagers to join Earthwatch Institute小题2:What’s true about their journey?

A．They had to pay for their journey at their own expense.

B．They often had to move from one hotel to another.

C．They had to take great pains to collect environmental information.

D．They received a warm welcome every time they arrived at a new place.小题3:It can be inferred that Earthwatch Institute could be _____．

A．an international university that takes in students from all over the world

B．a TV station that makes programmes on the beautiful scenery of the earth

C．a travel agency that organizes adventure trips specially for school children

D．an organization that brings science to life for people concerned about the earth’s environment小题4:What did they these teenagers learn from the journey?

A．It was high time that people protected the environment.

B．Long journey was not suitable for school children.

C．It should take the whole world to help the children.

D．Environmental problems can be solved if school children take part.

在X射线管中，高速运动的电子与靶相撞，能够产生连续X射线，在特殊情况下也能产生（）。

A、特征X射线

B、示性X射线

C、荧光辐射

D、以上都对