问题 选择题

关于成像情况,下列说法正确的是(  )

A.平面镜成虚像,凸透镜成实像

B.光的折射可以成实像,也可以成虚像

C.光的反射成实像,光的折射成虚像

D.光的反射不可能成虚像

答案

A、平面镜能成虚像,是光的反射形成的,凸透镜既能成实像也能成虚像,所以此项描述错误;

B、凸透镜成像是光的折射,成像时可以是实像,如照相机、幻灯机等;也可以成虚像,如放大镜,所以此项描述正确;

C、光反射时一般成虚像,而折射时可能成实像,也可能成虚像,所以此项描述错误;

D、光反射时成虚像,如平面镜成的就是虚像,所以此项描述错误;

故选B.

阅读理解
根据短文内容,填写信息卡。
    According to the Center for Disease Control and Prevention (CDC) (疾病控制预防中心), if you don't
often wash your hands, you can pick up viruses (病菌) from many places and make yourself ill. You're at
risk every time you touch your eyes, nose or mouth. In fact one of the most common ways people catch
colds is by rubbing their noses or their eyes when there are cold viruses on their hands. If you don't often
wash your hands,especially when you're sick, you may spread the viruses directly to others. You should
wash your hands in the following situations:
    ●After using the bathroom.
    ●After blowing your nose or coughing. 
    ●Before eating, serving or preparing food. 
    ●After touching pets or other animals. 
    ●After visiting anyone who is sick. 
    ●When your hands are dirty. There's right way to wash your hands. Follow these simple steps to keep
your hands clean.
    ●Use warm water (not cold or hot)
    ●Wash for 15 seconds.  
    ●Rinse (冲洗) well under warm running water and dry them with a clean towel.
                                                   Information Card
Way to protest against (防止)
 the spread of illness
1.                   hands.
Correct way to wash your handsUse 2.                   running water.
Situations in which you musy wash your handsAfter using the 3.                   .
Before having 4.                   .
After visiting 5.                    people.
Time needed wash your hands15 seconds.
选择题