下列物体运动现象属于离心运动现象的是 A．火箭加速升空 B．洗衣机脱水 C．航天
题型：选择题
问题：
下列物体运动现象属于离心运动现象的是
A．火箭加速升空
B．洗衣机脱水
C．航天员漂浮在空间站中
D．卫星受稀薄空气影响圆周运动轨道越来越低
题型：选择题
Do you know Weibo? Do you write a Weibo? If you don't, you are "out"! Weibo means microblog. People may spend muchtime writing a blog, but it takes a little time to write a microblog.Why? Because every message on a microblog is less than 140 words.
Microblog started in the USA. It came to China in 2009 andit has developed very fast. In 2011, the number of Chinesemicro-bloggers grew to 300 million. Now, more and more people are interested in writing microblogs. For manymicroblog users, it is a great way of learning the freshest news,talking with friends and sharing different kinds of information, including news, daily life, pictures,music and so on. Many stars and famous people also write microblogs and share good things with theirfans.
It is easy and fast to send a message on a microblog. However, this can also lead to problems and even cause panic . For example, when thebig earthquake and tsunami hit Japan in March, 2011, messages like " Salt can protectpeople from radiation" were hot on microblogs. It soon caused a crazy buying of salt. Later people realized it was just arumor (谣言).
In a word, microblog plays a new role in the life of Chinese people.
小题1:People spend _____ time and _____ words writing microblog.
A．little, a few
B．a little, few
C．a little, a few
D．a few, a little小题2:There were 300 million Chinesemicro-bloggersin _____.
A．2008
B．2009
C．2011
D．2013小题3:Which of the following is TRUE?
A. Writing a microblog needs a special training.
B. Microblog appeared in China only one year ago but it has developed rapidly.
C. As a popular thing, microblog has its advantages and disadvantages.
D. More and more Chinese show great interest in microblog because it started in the USA.