阅读理解。 Reader's Digest is a monthly maga
问题：
阅读理解。
Reader's Digest is a monthly magazine. Before the 1980s, it belonged to a privately held company,
which was started in 1922 by Lila Bell Wallace and Dewitt Wallace. This magazine is small and easy to
carry, just half the size of most American magazines, which caused a phrase in 2005, "America in your
pocket." It is the best selling magazine in the USA. At present, its circulation(发行量) in the USA has
reached 10 million copies and the number of the readers there is 38 million. Its global circulation outside
the USA has reached 40 million people throughout more than 70 countries in 21 languages.
This magazine's focus(焦点) is not news but more of cultural views because the editors think people
now can get timely news from somewhere else. They hope this magazine can give readers something that
is about special personal experiences, something the readers can share with their families. In different
countries, this magazine provides a window to the world for the local readers. Some parts of the
magazine are about the local customs and interests of the local readers. The other parts give the local
readers information from all over the world.
This magazine actually used to be a family business until the Wallaces died in the 1980s. Because they
had no children, there was no one to take over the company. Sixteen years ago, this company went public and became a public company.
1. How often does Reader's Digest come out in the USA?
A. Once a year.
B. Once a month.
C. Once a week.
D. Once a day.
2. What's the number of the readers of this magazine all over the world?
A. 38 million.
B. 40 million.
C. 78 million.
D. 108 million.
3. This magazine's focus includes the following topics except _________.
A. something about the timely news B. some special personal experiences
C. some information from all over the world
D. the local customs and interests of the local readers
角，如图所示，若此粒子在磁场区域运动过程中速度的方向改变了120°，粒子的重力忽略不计，求：