问题 选择题

关于速度、速度的变化量、速度变化率的关系,下列说法中正确的是(  )

A.速度变化为正,速度变化率可能为负

B.速度越大,速度变化量一定越大

C.速度的变化率为零,加速度也一定为零

D.速度变化量越大,速度的变化率一定越大

答案

A、速度变化率也是指速度变化的快慢,是速度变化量与时间的比值,是个矢量,其方向与速度变化量方向相同,故A错误

B、速度变化量指的是一个差值,用末速度减去初速度,速度越大,速度变化量不一定越大,故B错误

C、加速度就是速度变化率,故C正确

D、速度变化率是速度变化量与时间的比值,与两方面因素有关,故D错误

故选C

阅读理解

Read the passage and answer the questions. (阅读短文,回答问题。)

                                                   The Fashionable Tang-style Costume

    Located① in Changle Road on the side of Shanghai Jinjiang Hotel, the “Tang-style Costume Street” has been enjoying high popularity for its traditional Chinese attire② following the costume pattern of Tang Dynasty (618-907) . Its fame③ soared④ higher after the APEC⑤ meeting in Shanghai at which Tang-style costumes were offered for APEC leaders.

    On the street are custume shops of various grades and features. Some sell modern costumes with traditional touch, such as cloth-knotted⑥ buttons and round flower patterns. Others offer 100 percent traditional attire. 

    Most shops sell costumes, so you can enjoy the Chinese costumes. Why are the Chinese costumes so popular now? It's in touch with the high development of our country. The getting-in-fashion was also owned to APEC leaders. They all wore Tang-style costumes at Shanghai meeting. This has proved an old saying that only things of a national touch can prevail⑦ in the world.

Notes: 1. locate   v.  位于,坐落于

           2. attire   n.  服装,盛装

           3. fame   n.  名声

           4. soar    v.  猛增

           5. APEC  亚太经合组织

           6. cloth-knotted   adj.  用布打结的

           7. prevail  v.  流行 

1. Does the Tang-style Costume Street locate in Shanghai?

                                                                                          

2. Where did APEC leaders wear the Tang-style costumes?  

                                                                                          

3. Are the modern costumes with traditional touch in fashion? 

                                                                                          

4. Most shops sell Tang-style costumes, do they?

                                                                                          

5. What's the old saying for the fashion?

                                                                                          

单项选择题